Voice of descent here, sorry.
I imposed a trigger shifter (9 speed LX) on my daughter when she was 7 and she really didn’t get on with it, instead of just refitting the old revo-shifter though I fitted a SRAM gripshifter (Rocket) which was definitely easier for her to operate.
When it came time for a 24″ bike I asked her what she would like, and let her try the various clicky things on my bikes, she still wanted gripshift, this time I fitted an all SRAM drivetrain, the lower cable pull ratio definitely requires less force to move it which is a pretty major benefit for smaller handed people.
So (IMO/IME) yes ‘Revoshift’ are toss, but SRAM gripshift are a better and more viable option for kids, and most importantly actually ask your kids what they would prefer to use…