Yo so long story short yesterday I got scammed out of $80 by USfine and I could care less about that, what i'm more worried about is that they asked for a picture of my ID to prove that I was the paypal account holder and like an idiot I took the picture.
Should I be rushing to get my ID info changed before someone in china jumps with my info
Most gold selling sites use this as a means to deter fraud and fight chargebacks. The practice for the most part was copied from PlayerAuction's standard operating procedures. Although there are slight differences.
In addition to the above reasons, PA also does this as a
requirement to fulfill compliance issues relating to AMA and KYC. It's complicated, but the fact that a) we are a marketplace and do not sell things directly and b) we are a marketplace
that hosts virtual currency exchange means that we need to do our part in order to comply with US regulations on c2c and currency exchanges.
More to your question, the difference between say, PA, and USFINE, is that the latter is (as you said) a China based company (do a whois lookup at domaintools.com, and it's easy enough to find). They can do what they want with no repercussions. PA on the other hand is subject to US laws because we are a registered US business, have our banking stateside (meaning our assets could be frozen if we broke the law), and our hosting is there (not to mention, several of us within our 4 international offices are US/EU citizens, despite having operations in Asia).
Where PA is liable, a company like USFine is not (in fact, most RMT businesses are not liable, even reputable sellers who are based in the US, most are not US registered businesses).
Do Chinese companies abuse ID's? Not that I've heard of... but it
is possible, with limited repercussions.
That being said, the probability of shenanigans happening may not be terribly high, but it may be better to be safe than sorry.
While my notes may seem like shameless plugging (sometimes they are ^_^), the reality is, I want to
help, and there are
always nuggets of information the savvy reader can find to make themselves more professional/aware/or expert in this particular area

I hope it helps. The more aware and seasoned traders there are, the better it is overall for removing the stigma of secondary markets, which is a goal we'd all like to see happen.
Why did you chose USFine to make your purchase in the first place?