Correct me if I'm wrong, but you don't want how returning to spawn point upon entering the world to be abused and make recall potion/magic mirror obsolete, right?
But the way I see it, it's gonna be abused and make something obsolete either way. Since if you enter the world back at the same location, that's mean bed is obsolete instead.
Comparing those two just from legit gameplay mechanic, going back to spawn point has always been easier, it's just one click on one item (and even free with mirror). On the other hand, building a spawn point take comparatively a lot more effort and never an instantaneous action to do. I would say making the hard one harder to abuse is the correct design choice.