E-bikes with properly adjusted mechanical disc brakes are perfectly safe, and mechanical brakes are easy to adjust yourself without the need to take them to a bike shop. It's the discs that are important -- not whether they are mechanical or hydraulic.
If you put miles on your bike and ride hills, you'll spend way more time fiddling with an allen/torx on the inboard pad or the adjustment barrel on the cable as your pads wear. The bleeding procedure for hydraulics is for sure messier, but still very doable in 5 minutes. When you do have air in the system, pumping the lever a bit gives you back some braking function.
