Wine is amazing but it still is not the same as native support, because of small performance hit or possibility that game that you bought will stop working in the future (ie: because some game patch or anticheat protection that will detect wine as modification). Because of that Steam and Source games are very welcome. Probably I'll buy them and don't play them because of lack of time(just like all HIBs).
Good point , I've had a few programs that I was happily using in Wine suddenly auto update themselves and start crashing all the time or cease working at all. For this reason I simply couldn't recommend using Wine to anyone who requires a particular program for their work (unless the developer specifically targets Wine as a supported platform , such as XMLSpy).
Also some games have DRM which does not work with Wine, so the only way to get it to work is to run a cracked version. Steam should fix that.
Also some games have DRM which does not work with Wine, so the only way to get it to work is to run a cracked version. Steam should fix that.