Relying on Vsync can be a very bad idea. Many PC gamers will avoid it like the plague as the input lag is terrible. Of course it depends on the game but input lag is never a good thing so even less competitive, slow-pased games can feel terrible with it. I’m not usually that picky with games but I refuse to play any third/first person game with Vsync on and many are the same.
Also having higher frame rate than your display’s refresh rate isn’t a bad thing, it’s not going to cause more screen tearing. What causes tearing is if the frames doesn’t sync up (doesn’t happen if you use vsync, freesync or gsync). Also if your GPU can push out more frames than your display need, it will ensure the frame that is shown is more recent than when having a lower frame rate. This reduces input lag, so it’s definitely not a waste to be able to push more than your display can show.
Other than heat reduction or battery usage and such on weak devices there is no reason to not let it render more frames than the monitor can show. What can be beneficial is to let players set a max limit on FPS that is the lowest fps it drops to during gameplay. This ensures the fps is steady and input lag is constant which is helpful for competitive games.