I’ve developed some mobility issues as I’ve gotten older. I’m tall enough/not overly long armed enough that 22” means I can’t pick stuff up off it without having to bend/stoop, which I can do but aren’t ideal. Actually just measures my bedside table and it’s 27” and just about right. 22” would absolutely be too low, putting it about 6 inches below the top of my mattress, which means I can’t see or reach the CPAP machine without basically getting half way out of bed.

This of course depends on how high your bed frame is, and how thick thick your mattress (and potentially box spring) are.

22” is pretty typical for an end table next to a sofa. For someone with a relatively low height bed it might make sense as a bedside table too.