I would NOT keep a 'version' of a song where it is obvious that it is the same version sung off-key and with forgotten words.
It's still information about the distribution and evolution (or not) of that song, but if it's a matter of storage space....
I see the love for the music even in poor performances. If that is missing as well then I might take a different view. In my experience, there is very little second best; you might need to be quick at the bar. With encouragement, second best quickly gets better.
Please let's not turn this into a point scoring match; I've got things to do.