Here's what I think...
Does the 1FBUSA have an AF? If it doesn't have an AF, I'd probably sock drawer it.
Do you always PIF? If you do, then the crazy 30% APR won't matter
I don't know my credit score either and I don't have DISCOVER but I say go for it.
If AF means annual fee, then yes. However, I filed a BBB complaint and asked that they remove it yearly automatically. At first I had to call in order to have it removed, but then I just decided to complain and I demanded that it be removed automatically every year.
Yes. I always pay in full. But then I'd rather have the Discover or another offer like one of the promotions from American Express which are at 0% for 15 to 18 months and with no annual fee.
I just see the 1FBUSA as not needed. But I don't want to harm my credit score. I'd rather have some or all of that $17,500 fall under Discover or American Express.