I didn't automatically figure that paint & primer in one couldn't
work, as some people (i.e., not paint chemists) immediately concluded.
Figured it's possible that there's enough room for each's properties.

So I had high hopes.

Then I tried it. Won't be buying it again. Didn't stick as well as
primer. And didn't seem to hide as well as paint. Had to do two coats
anyway, three in a few spots.