unless this doesn't alter the sensitivity like playing in 1080p does which I doubt, I disagree. Also, chances are people would have to add custom resolutions to windows(since they're not "official" resolutions) which would be too much of a pain with people who don't know much about computers.
if you go into your gfx card's properties and click on "list all modes" you wont see 799x599 and for that reason, you won't be able to use it full screen until you add it I think and to add it you gotta use a 3rd party app.