Inevitably you end up with some lenses which don't require an adapter as well as some which do require an adapter. So you have to mount the adapter to the body and then the lens to the adapter. Then you have to take the lens off, then the adapter off, then mount the next lens (which doesn't require an adapter).What is the difference between mounting a lens to a flange on a body and mounting it to a flange on an adapter? I haven’t noticed any difference myself.
If you never want to buy a new lens ever again, by all means just leave the adapter on the body 100% of the time.