Regarding back up ... I haven't done it, but I should have backing tracks for about 2 hours worth (for variety) of songs on my tablet, JUST IN CASE something happened to the kb during a 'senior' gig ...
But along with singing, my joy comes from PLAYING my kb - initiating chord changes, playing fills, playing a solo during the song ...
As some here may remember, in addition to my solo work, I did sing to backing tracks with a female vocalist for a while ... She has retired for health reasons, and while I thoroughly enjoyed performing together, it did not give me the satisfaction that playing and singing does ...
But that's just me ...