Not true for a fucking second. You'd never use the rokinon for true landscape stuff, and you'd definitely not use it in low-light situations.
there are other options though, if you're looking to be price conscious, and don't care for the speed, or would like a little more range, look into either the Tokina 12-24 f4 or the Tamron 10-24 f3.5-f4.5.
Both will run around 350-400, and be very good for many of the same shots, with a little more zoom range than the 11-16mm tokina. You'd have a slower lens, but if you're using it for skiing, where you stop down to at least f8, or more if it's sunny, then it will work awesome.