First I want to say I'm biased, I'm working with Windows 40+ hours a week and it sucks... I hate it!
At home I'm using Steam under Linux Mint and I just bought the game to show some support because I really liked OPF*1. If you see Humble Bundle statistics you will find that Linux or Mac users spend more money. With Windows becoming more closed it will deffently be a good step to at least plan for it so it could be implemented at a later time. If you add a wrapper layer at this time you may be able to switch later very easily.
*1 I started looking at games again because I pledged for a Oculus Rift, I didn't play much for the last 10 years... just think about it, there are many older people like me that stopped playing because of all the trash that came out in the last 10 years; you will be able to tap into this generation (and at this point we have much more money).

I don't see why not?