Why is a mid-motor preferable? Doesn't it introduce an other point of failure at the chain because of the additional torque, which is not present when having the motor at the rear? I always thought, that having the motor where the force is needed would be better, because there isn't any conversion necessary.

So I never considered buying a mid-motor ebike.

Crank motors are generally much more responsive than hub motors if used for pedal assist (as is required by law many places).

Having it apply torque via the chain/belt also mean you can gear the motor output on your back wheel.

Why people dislike hub motors.

They weight near nothing for power levels legal on bicycles.

Even on low end mopeds, motor weight is not that big of a problem.

It is at power levels of around 7.5kw, when it becomes a problem.