The Day the Music Died.
There's a huge difference between a musician/singer, and just a singer, and a video. It's one of the reasons I will watch 'unplugged'. There's a huge difference between those who do their own material and those who do only staged videos or sound tracks and sing other folks' stuff.
The latter might have a good voice, but they are essentially quality karaoke singers as opposed to being musicians. And then there are those song and dance and drama routines that never see an unplugged stage.
The truth is that you don't really know if they can even sing.