If your wood for your wall is bowed, and you match the bows, your wall will have a slight bow or cup depending on which side you’re looking at. If you don’t match them, it adds strain on your drywall and may cause deformations. The taller the wall, the more obvious this will be. If your wood is doglegged, it will be almost impossible to match that. Twisting is more of a problem because if it’s bad enough you’re either going to spend a lot of time and fasteners correcting it or you’re going to have a board that doesn’t line up with the rest of them since a board on the diagonal has a greater depth than a square board. This can also cause problems when attaching drywall.

It’s less hassle, and possibly less time wasted picking better boards for your project than it is correcting those defects during your project. It also doesn’t cost any more.