Yeah I don't think you could do rotors.
These use to be used for many things Mill is used for today, as and there are things the Shaper can do the mill cannot. As pointed out it can provide a very nice FLATsurface, it will dovetail without the need to spend a bunch of $$ to buy special cutters, you could use it to checker I suppose but cutting keyways (can't do that on a mill) and gears without special tooling or if you need a square hole in material (try that with round cutters in mill) is where these shine. You just needed to grind the HSS tool bit (like a the ones used in a lathe) to the proper shape and go at it... It has an automatic feed with adjustable feed rate so you set it, start it and just let it run.
It works really well, I just bought it on a whim and haven't used it since I have a mill and lathe, and the shop is getting a bit overcrowded so it is time to thin the heard a bit.
DonT