Hi AlanF, it should be a simple matter to calculate power sent into the battery during a charging cycle - this is just mA integrated with time. I expect the measurement to be reasonably accurate. I agree that it is the discharged power that counts. If we assume that the charged power is measured consistently (even if not accurately) and that there is a reasonably good relationship between charged and discharged power, then the relative charged power of two batteries should give a reasonably indication of comparative capacity. This indicates that the Wasabi is about 5% less than the Canon, even though it claims quite a bit higher.
Hi MSP, the Wasabi battery is near new (just two charge cycles). I don't know how many cycles the LP-E6N has had - I got it new with my R in October 2019 and rotate four batteries through the R. Its still showing 3 green bars in the R battery health indicator. I think the comparison is fair.
As for burning the house down, I haven't read of any situations where Wasabi or Watson batteries have damaged cameras, although there are a few reports of batteries swelling and being difficult to remove from Olympus cameras. My father flies radio controlled aircraft. The lithium batteries he uses to power the electric motors in his planes do combust from time to time (they are a different form of lithium) - he stores his batteries in a ceramic pot with a lid!
I've always used Canon batteries in my Canons (300D, 20D, 5D, 5DII, 5DsR, 6D, M3 and now R) until now. Previously there were issues with incompatible chips, but the Wasabi is fine. I'm not concerned about damage. The question is the length of life. Let's see. I'm also interested in the new battery in the R5.