Even though I have 2 full-sized hybrid e-bikes and bought the folding Fiido D11 only for the necessity of commuting/taking on trains, in reality I'm finding I'm using the D11 more and more in daily use, even in preference to my full-sized e-bikes.
The compact nature of the D11 (as with the D21) has a "grab and go" appeal, whereas my full sized e-bikes seem to need a mental adjustment of "getting ready to go" about them - which is fine on a planned day-trip out for excercise or leisure riding/touring.
The other appeal to me of the D11 is the effortlessness of a cadence based system, whereby you can choose to put effort into pedaling or not if you're feeling tired or lazy. That compares to my other e-bikes of torque sensing, as with the D21 & X models, where it demands you put at least some effort into pedaling.
I do now wonder if the torque sensing D21 and Fiido X had been available at the time I bought the cadence sensing D11 if I'd have chosen differently. Somehow, I'm glad that choice wasn't open to me.
My first brand new full-sized e-bike was cadence based. I hated it and sold it very quickly, preferring instead Torque sensing e-bikes thereafter. Now though, I'm seeing the appeal of cadence, as other members here have long advocated.
I guess it's horses for courses. I hope
@stormfeet keeps this thread updated on his D21.