Yah, I'm a mid-drive fan as well but for the guy who wants to pedal without using any electric motor power always except when climbing hills the fact that a mid-drive is just as effective in the highest gear as in the lowest gear can often be too much of a temptation and you end up not saving your battery power for when you need it to climb hills (assuming a minimalist light weight battery set-up). Using a second chain and doing a fixed low end gearing to the rear wheel on the electric motor accomplishes the priority of removing the temptation to use the motor except when it is needed for low end power for climbing hills or accelerating from a dead stop with a heavy cargo load because its pointless to use the motor at flat land cruising speed because it doesn't do a thing because it is geared low enough that you are already going faster by pedaling alone then the motor can go.

So long as you can resist the temptation to use a mid-drive on anything but the hills it will work for just a hill climber motor but very few people have that kind of self control and sooner or later they will end up getting a bigger battery and running it most of the time.

So it depends on exactly what one's goals are, and you should build in both negative and positive incentives to match those goals to both push and pull the rider into riding the bike as it was intended rather then being lazy and letting the motor do all the work and not doing their part.