How is it silly? I've used Debian Stable and Ubuntu LTS on desktops for many years. I've always had the latest versions of all the apps I use thanks to backports, repos managed by upstream developers (e.g., PPAs) and occasionally installing software from source. (Disclosure: I don't use GNOME, KDE or any other DE, which can be problematic to keep updated.)
Also, many upstream developers who provide packages for Debian and Ubuntu (e.g., PostgreSQL[1][2] and Spotify[3]) only test their software on Debian Stable and Ubuntu LTS.
Lastly, Debian Testing has the worst security update speed and should not be preferred if security is a concern.[4]
[1] https://www.postgresql.org/download/linux/debian/
[2] https://www.postgresql.org/download/linux/ubuntu/