I recently made a switch over to the PC where I now play the vast majority of my games. Mortal Kombat is one of the (very) few reasons I'm holding onto my 360. But I would much rather the game on PC, no doubt about it.
Few points -
It makes sense financially. Sales may be less on PC but profit margins are much higher than console. There are no console licensing fees nor packaging and distribution costs for selling the game online only.
The game is also pretty much done, a decent port is pretty quick and easy to do and will not hurt anyone.
Control options are not a problem on PC, it's more flexible than console there.
Fighting games are pretty thin on PC, releasing the game for a respectable price on a service like Steam will see PC gamers respond with buying the game (PC game prices are tradionally less than console, i.e. Portal 2 and The Witcher 2 at $US49.99 is reasonable).
Trying to gouge PC gamers with console prices like $US60 and up or doing a shoddy port will result in increased piracy and poorer sales.