I brought it up two posts ahead of you.Page 3 and still no mention of catios? These are fairly common in the PNW - not entirely sure why.
https://i5.walmartimages.com/seo/Pa...peg?odnHeight=2000&odnWidth=2000&odnBg=FFFFFF
They put one of these in our local animal shelter, attached to a communal indoor area for the more social cats that were up for adoption. Cats were mostly using the indoor area. Just a small sampling.
I didn't build one because of concern of some of the outdoor cats around us getting to my cats.