I don't understand the complaint. It's useful especially for people not riding every day or dozens of km on weekends. Sure, press or rotate to go up or down, but then you end up cross-chained on the largest chainring and largest cog.
I have had bikes that did not have numbers, but at least had indicators giving you an approximation where you're at. I sometimes miss that on my road bike when I'm not sure if I should change the gear on the front or not. When you ride enough you get a feel for it, but again not everyone does that.
i guess i ride enough - not dozens of kms or daily, but over many years - to intuit the gear, which is helped by the gear mechanism jumping to discrete positions. The first bikes i rode with gears were Marins back in the 90s which had no indicators, there was an old 3-speed Sturmey Archer (had to Google this one) where the gears are within the hub, I don't recall a gear indicator for that, but perhaps there was
I have had bikes that did not have numbers, but at least had indicators giving you an approximation where you're at. I sometimes miss that on my road bike when I'm not sure if I should change the gear on the front or not. When you ride enough you get a feel for it, but again not everyone does that.