In all honesty it all depends on where in the world you are. I used to do wood working as a hobby, anything from cabinets, speaker boxes, some tables, and guitars. If I leave a piece of regular plywood outside (anything smaller than 1/2") and it got wet, it will coup. Let alone keeping it under soil watering it daily with a bunch of nails stuck in it.
We do share more than one hobby then
The North-East of France isn't exactly known to be dry... it tends to be agreeably moist throughout the year. Same thing with Japan... it's normally very humid. My garden is unusually extra moist as there's a major river running at the back, I am surrounded by my own private wood and it turns into an island for a few months every year. We do have roughly the same average rainfall in the year, but I'm getting that in about 8 months of wet weather. You get an average of 71 days of precipitations, I get an average 180 days of rain and 24 days of snow
This is a 1/4" plywood root board that spent Spring 2020 in a pot, then was left exposed to the elements since. As you can see, it is starting to delaminate on the edges but is still surprisingly intact in its second season growing seasons outside. The delamination has only started this month. It's not even a fancy plywood, it's the cheapest interior grade plywood sheet I could find at a discount big box store. It would probably last a whole lot longer if I used some spar varnish on the edges.