I would say it is worth it.
But it is also a matter of opinion.
What I suggest you do is to set up your PC and test some vertical games (pacman, donkey kong, galaga, etc) with the screen in horizontal mode.
After a few games, turn your monitor vertical, set mame to turn the screen and play those games again.
I bet you will see a huge difference.
But again, it is a matter of opinion and what suits you.
Monitor rotation is a lot of extra work, but several on here have paved the way, so to speak, so you can dive into it without having to do a whole lot of trial and error.
Plus the awe factor is very satisfying when your friends choose a vertical game from the front end and the screen starts to turn.
Good luck on your project, whatever you decide to do, and rest assured the resources for help on here are always available to you.