One thing to consider with mid-drive weight is that you're replacing the existing crankset... On folders they usually weigh about 1.5kg... so it's worth considering that the added weight = (weight of middrive - 1.5kg)*
Adding hub motors means adding weight of motor and possibly a heavier wheel too??
Could get lighter crankset with hub motor to remedy that but doesn't seem worth it imho, given added cost, extra wiring, and lack of portability if you want to move to bike with different wheelsize later on.
*Please correct me if I've got this wrong, I'm a newbie too so could be talking rubbish.
The 15 .kg probably doesn’t include the pedal arms, which are square taper. There aren't many light square taper pedal arms compared with Hollowtech type. I would have thought that the first thing aybody would do if they wanted a light ebike is to look at the crankset, seat, seatpost, tyres and stem.
Another consideration using your own argument is the weight of the hub and axle that's included with the hub motor.
The argument about heavy rims and spokes doesn't hold any water. You can use whatever you want with whichever hub motor you buy.
I've done many conversions with both crank and hub motors. For the same performance, hub motor systems always work out lighter, except when using the very high power crank motors, like the BBSHD, but then all the other crank motor disadvantages become a higher concern than the small weight difference.
I reserve judgement on the Gospade crank motor. I cannot believe that its going to be reliable at that weight and with the performance they claim. I can't see how it's going to shed its heat. Someone needs to give one a thorough testing. Maybe that someone is you.
The main point, anyway, is that cranks motors are just not as good as hub motors for commuting. They're less reliable, less dependable, less covenient and more unpleasant.
I keep saying, when people use the argument that a crank motor is easier to fit, why would you want to save an hour of work to condemn yourself to years of less pleasant cycling and give the time back and more when you have to replace all your chains, sprockets and derailleurs?