stolen credit cards much?
Nope, these are almost guaranteed to be cracked accounts. As long as you don't make a new user on them or change the pass, these are great for personal use.
It's not hard to sell them for $3 each. 1500 x $3 is $4500, but assuming you only get 100 customers or so you can still expect a good pay.
Not to mention that these are free to get in bulk on many websites.