I have not tried them but I do a lot of riding in soft and packed snow in western mountain snow. We don't even have to use studded tires here, so take that for perspective. The three biggest problems I face are:
1) lack of floatation. I don't think these will help at all with that. Wider tires (4.5-5 inch) at 3 psi are the best solution we have for our conditions.
2) Lack of rear wheel traction leading to tire spin, especially when climbing hills. These chains might help with that if they sink into the snow more than the tire knobs. I often envision deeper tire knobs when this is occurring.
3) Front tire washout to the side, especially when you hit even a minor rut, or when riding on a side sloping incline. These chains don't have a side stability feature that would help with that. If they had a crisscross pattern, they might help considerably.
I suspect they might be a real improvement in very hardpacked, almost icy conditions. Like in a well packed parking lot or side of a well traveled road. But when the snow is hardpacked, but still white, the rubber tire compound gives surprisingly good traction. Snow crystals are rather jagged in shape so the rubber gets good traction on that.
The biggest problem I see with ebikes in the snow are with the more powerful throttle based class 2 and 3 type bikes, coupled with less developed riding skills. Especially when combined with crude software controls that put a burst of power to the tire at start up. That spins the tire and makes a rut in the path. And the rider can't get going anyway. I have seen that too often. The class 1 typically has less (and smoother) power. The pedal assist nature of the class 1 ebike forces the rider to sit down to pedal to get started, thereby putting more weight on the rear wheel to improve traction. At least that seems to be the current state of the technology.