Steam 10% Price Difference Policy

I'm also not sure whether or not to open another giveaway to get rid of my steam wallet change or not, but there's only so many questions to ask in a single poll, and usually that numbers only 1

People are on Steam in first place because they want to buy AND play a game, not to beg for "free stuff". Giveaways are a way to dispose overstocks, and a way to show generosity...or to show so called "elite stuff" for "elites".
Local stores were already suffering, but after regional prices, things became much better, and I joined when they introduced my local currency. But worse things happening overall on steam, like digital homicide were only in beginning...
On topic of CV level, you can give ANY bundled game, as long it's not massively given away. Example of massively given away games are Racer 8 - it gives no value, and is mostly forbidden.
Games that are AAA or not bundled/massively given away, are however, fine. They give full value of their store page cost. Bundled, like Frozen Synapse Prime give only 15% of store page value.
So yes, people like to make giveaways for "elites" for the "elites". But most are lvl 0-1 anyways, expect special ones you can find on discussions and from other users.
Using a platform for giveaways instead of supposed gaming as your point is already ENOUGH to make people mad at you by adding you into blacklist.
On region restricted giveaways, you must tag them with regions they supposed to work within; example if gift is RU/CIS countries(i.e Russia, Ukraine, e.t.c.), you must select RU/CIS as region for gift to prevent failing to give it for people who can potentially win.

Steam applies unique price for each region. GTA V costs 60$ in US store but it only cost ~ 23$ in Asian store. In order to prevent people from using VPN to buy cheap game in such regions to resell in other regions (where games are more expensive), Steam put region restricted policies. For example, if you buy a game in Southeast Asian region, you only can activate them in that region. If you give the game key/gift to your friend in other regions, he/she will not be able to activate it. US region is the most flexible region IMO. If you buy game in US Steam store, you can activate it everywhere

I wish that instead of forbidding buy-to-gift, they'd offer an option to buy at the target region's price — I have friends in other countries, and this limit simply makes things unnecessarily complicated for personal use.

For steamgifts, though, I definitely prefer using keys, they're much more reliable.

how to know what's region restricted or not when buying gifts.

Everything through Steam client is region-restricted now, as you've discovered. Most of us (at least, of those of us who I've seen discuss the topic on the forums) have stopped using the client as a resource for giveaways. However, if you do end up using it in the future, you can check comparative pricing by searching out the game in question on SteamDB.
That said, as you're in the United States, your considerations actually end up being rather reliable- as a rule, you should usually be safe giving to any region not utilizing the Euro, and will never be safe giving to the countries which do utilize it (as other currencies usually hover at no more than 5-6% above USD, while the Euro is always up around 15-20% over USD; I believe the pound will really typically be the only one you'll need to pay mind to). Alternatively, if you don't want to take the time to filter out individual countries, you can play it safe and just region restrict to the US only.

I have family in Europe and I am unable to buy gifts for them from Australia with my Steam wallet. It's very annoying!

I had that problem over the holidays - I had a few friends I met through here that I wanted to buy some small holiday gifts for, but I couldn't due to region restrictions.

What I did in that case was I bought them a steam gift card and nudged them toward the game I would've gotten for them.

I can confirm, that Steam 10% Price Difference is only in charge if you in the region where the price is 10% lower.
You can always give a game to a region where the game would be cheaper.

Steam is pretty dumb about this anyway. They could just automatically convert the price and make more money if a person chooses to buy it anyway.

Steam for giveaways?
Creating a giveaway on steam = you will not get anything.
Creating a giveaway on steamgifts = you get cv + higher level = higher chances to win games.

In all cases it is better to create a giveaway on steamgifts instead of steam.

After the gifting change, and getting denied on like 4 things last year, I've pretty much stopped doing Giveaways bought on Steam.

Steam itself stopped being a good source for giveaways since gifting changes. Most of the time you can get ROW key for the same (if not lower) price, from reliable source (such as HumbleBundle or IndieGala), and with far less hassle.

Personally I've stopped doing Steam giveaways for all public (including invite-only) giveaways, I keep them mainly for my group members I can trust on in case something bad happens. Even in this case I use it sparingly, it's just not worth potential hastle if I can buy from other source in the first place. I spend eurogabens obtained from market and other sources for gifts for friends instead (as in this case I can just buy them something else, from another source, if needed).

Never use steam for giveaway
It's a no-no since u never know the price difference. Go for keys(it's better)

the only steam giveaways I did were for things already on my gift inventory
if you wanna do a steam giveaway you should make it region restricted to where you live because of that
in general, the best is to go for keys if you wanna do giveaways