I’ve done it a few times but it included also swapping the pedals between my bikes. It can be done, but I found it too much of a nuisance doing it a couple of times/wk so just got separate power meters.
I swap between SPD and SPD-SL bodies every few weeks, it takes about 10 minutes total. I don’t see that its really adding any extra wear and it gives me a good excuse to clean and grease everything.
My biggest fear with the swap is stripping the screws. It happened once on my MX. I sent it back to the factory, and they replaced them free of charge.
I think they’ve improved/revised the screws since the original MX release. I was cleaning up a set of MX’s and they had a fully red aluminium screw that was pretty easy to over-torque and strip. I recently ordered a refurb kit from Favero which included all the spare parts and the new screw is silver and feels much harder metal. Virtually impossibly to strip.
Yeah my original MX set started “chirping” and the replacement seal kit they sent came with the new style nuts too.
With regards to swapping the pedal bodies regularly… you will probably be fine but when the pedals were designed and they were thinking about reliability and robustness they will probably have assumed the bodies were swapped a couple of times a year.
Good news is that the majority or the parts that will wear are replacable or on the bodies - the only bit on the actual power meter spindle you would need to worry about is the threads on the end.