The real answer is that Tinder is easier, requires less investment, is easy to show friends ("What do you think of this one?"), and girls get a pool of easily filterable dudes.
Probably-okay alternatives are the paid sites like Match and eHarmony, if that's what you're looking for. But OKC is a cesspool. The last time I was on, in December, the girls weren't particularly attractive and I recognized nearly all of them from months (sometimes years) ago.
Female friends I talked to agreed: hell, I had one search for girls in DC and she was like "... yeah, no."