Nobody (neither mfr nor customer) takes this path for the sex appeal. This is a B2B product (train car) so BOM and TCO drive everything.
It’s in the train co’s interest to have working toilets (not too many, because they displace seats but some) and have them reliable and easy to maintain (else costs go up, maybe even they need more per train). This is why they care about a denial of service attack (btw an electronic one can tell the conductor when the toilet is locked for a grossly atypical duration).
So to that degree the interest of the carrier and the passenger are aligned. This applies to most of the carriage decisions (robust seating, working doors and brakes, and so on).
But the if the trains pass first inspection, then it no longer is a development issue but a maintenance issue. [1]
It's not as if train companies can afford to run a statistically significant number of carriages from different suppliers to see which one gives them the actual best bang for buck 5 years down the road.
[1] Rule-proving exception: the Fyra trains. https://en.m.wikipedia.org/wiki/Fyra
The short version: high speed trains failed and were eventually returned (2014) to the manufacturer for ~2/3rds of new price. (That's the exception part.) There have not been high speed trains on this traject since. (That's the rule-conforming part.)
Buttons flush with the surface or low profile levers such as the ones shown in the picture can me be more robust against certain mechanical attacks simply by having lower weight, lower travel, and being smaller (don’t need to exhibit mechanical advantage).
I’m a fan of simple mechanisms with no software in them whenever possible, but I don’t have to deal with the cost and reliability problems.