Ran it for like ~6 months
1. It hurts your eyes. Might have just been me but it gave me headaches and eye strain
2. You have to be closer to your monitor to see stuff properly, it makes everything much smaller. (probably why I got eye strain)
3. The benefits are negligible. If people are still using 4:3 out of preference and they don't have any issues, this is for sure unnecessary.
Just so people are aware though you don't have to run it in windowed mode. You can mess with your monitor resolution to get it to work. I used a resolution switcher to make it work easier.