>>1684160lol you should try riding a rigid bike fast on some harder mtb trails, it's (fun) pretty brutal. Modern mtbs are amazing when they're warranted, the brakes as well.
Suspension and discs mean you can ride a lot faster. So it's less safe if anything.
But yeah, rigid bikes are better for most riding really and I do get you about the simplicity aspect to it. Suspension should be more of a niche thing and I think it's specced less on new casual bikes than it used to be which is good.