The "casual" mode in SF5 is meant to just be a quick match with no ranking points on the line and no frills.
If you want in depth rematch options, that's what Battle Lounge is for. The "first to" option is godlike.
Yeah, it works for that. If you want to gain FM while you do it, and you come across a good player you wanna keep playing...or get that runback, it should be an option.