I think what’s going on here is that we’re arguing over the difference between “good enough” and “better”.
Properly adjusted and maintained cable brakes will definitely stop you. Rim or disc, no matter. The bike will stop. It sure will.
Hydraulic discs are better. Full stop (pun intended).
Does it matter? Probably not.
Some people struggle to learn new things. Others don’t want new tools. Some are more concerned about the mythological roadside repair than anything else. Mechanical brakes are good enough usually.
The advantages of hydraulic brakes have been adequately outlined here. If you can’t get your head around it, honestly it’s fine. Cables will get it done.
A little FWIW, a car has 4 hydraulic brakes. The e-brake which barely works is cable. The car is slightly heavier than a bike though.