Yes, yes, it does make sense! I was in Surselva last weekend (bio-biking) and climbed 1400 hm and achieved an average of 164 W on this day (incl. downhill) (approx. 1600 kJ / time in motion 3:30 h). A weekend before, I reconnoitred a Jura bike tour to test whether the route is rideable with an e-city bike. There, (with the exact same watt pedal that I had remounted) for 1500 hm of ascent - mostly in eco mode but with very wet ground - I achieved an average of 176 W (approx. 1250 kJ / time in motion 2:50 h). Conclusion 1: All those who think that e-bikers don't need muscle power are very much mistaken. Conclusion 2: This is exactly what the Garmin Watt pedal is ideal for: it can be mounted on different bikes and measures the "bio-power" independently. Conclusion 3: I am very satisfied with my Rally XC 100.
See also: https://www.garmin.com/de-DE... and https://www.radsport-rennrad.de/test-teile... (December 2021), both links retrieved today.

I don't have the pedals on an e-bike. However, the watt measurements are very accurate.

As far as I know, the pedals measure the pressure you apply to them. Therefore, I would tend to answer yes.

I have it on my Gravel and it seems to be accurate there. It's only a one-sided measurement, but my Assiomas say that my balance is 50/50 or sometimes 49/51, so it fits. I don't see any reason why this shouldn't be correct for the eBike, the pedals measure this themselves. But I wonder what the point is of mounting them on an eBike.