With one ID you can create more than one PM accounts where someone can send you balance. Now, there are 4 type of accounts and one of them is BTC account. The difference for sure its rate, which is using BTC rate.I really don't understand this, is that there is now an option to use BTc on PM or that you have to open a second account for that because I really do not seem to see that on their site even though it's been pretty long I used it last.
So this is all about rate, if you have an account that are using USD you can convert your B account(BTC in PM) balance to USD account and vice versa. Not to mention that you don't have to open another ID just to get more than one account. Hope you got what i mean.