Can anyone play a 50fps video?


Hello everybody!

I was wondering if I uploaded a video in 50FPS to YouTube, would anyone be able to view that video? Even if their own hardware (pc/tv etc) is not able to play that amount of frames?
What will this do to the quality of the video if their hardware does not support 50 fps? Or will YouTube downgrade their quality to 480p (thee first one that is not 50 FPS)?

Sorry for these kind of noob questions ;-)

Nowadays all TVs/monitors/even phones screens can easily play 50 fps video by just duplicating some frames, like when you play 50fps video on a 60fps/Hz monitor