There is a package called popularity-contest that’s available in both Debian and Ubuntu (and likely other Debian derivatives). It grabs the list of packages installed on the machine and submits it to the Debian or Ubuntu popularity contests.
There you can see which are the most popular packages in Debian and Ubuntu. Unsurprisingly, dpkg, the package manager is rather popular.
Why should you enable it? Looking at popcon results are solid numbers as to how many users you may have. Although the absolute numbers may not be too accurate, it’s a sample set and if you examine the results over time you can start to get an idea on if your software is growing in popularity or not.
But there’s something more than that, if you can prove that a lot of people are installing your software on Debian, then you’re likely going to be able to argue for more work time being spent on improving the packaging for Debian.
Quite simply, enabling popcon is a way to help people like me argue for more time being spent on making Debian better.