Disc brakes have clear advantage over rim brakes, which can wear out the rim prematurely from the braking surfaces.
With smaller wheel diameter, the rims can heat up significantly on sustained downhill and result in flat tire while traveling.
If the rims are out of true, you can still ride the bike without annoying brake rub.
Yes, hydraulic disc brakes have clear advantages over mechanical disc, unless you're carrying significant weight like a cargo ebike,
or frequently traveling downhill over long distance; mechanical disc brakes are just fine.
Hydraulic disc brakes are overkill for bikes with smaller wheel & narrow-ish tires/rims.
Mechanical disc brakes are easier to maintain, no harmful fluids to replace, or source when you need to replace the fluids.
Brake cables are easy to find replacement.
Personally, I see the simplicity of mechanical disc brakes outweighs the performance that I rarely need for hydraulic disc brakes.