I use Putter Pal and Shot Pal as well and find them very accurate and a great tool. For most of the country clubs with level 5 (I think ) or above both of these are free so I'm not sure what revenue generation that is.
Much better than the old scales we taped on the computer in the past. You can easily disable it if you like. I view both of these as great tools and as I mentioned they are free from most country clubs.
I also use the course notebook, now that they fixed it the notebook is a great tool. I don't like having 10 home made tools, I'm much more happy to have things at my fingertips in a concise format.