The Skarper system is a unique take on the drop-in e-bike conversion kit, as the unit clips on and off of the chain stay, so riders can choose when they want to add electric power to their favorite bike and when they want to ride it without that e-boost.
Yes, even compared to a nice mid drive and top notch battery, it’s expensive. I guess you could make the argument that this is easier to add/remove but it still seems pricey IMO.