Testing doesn't get timely security updates. It's not for serious people with production systems. It shouldn't even be a debate.
Google disagrees - https://itsfoss.com/goobuntu-glinux-google/
The comment you're replying to makes clear that they're not using it on servers. I do the same thing (testing on my laptop(s), stable on my servers); you just have to commit to keeping track of what's going on and manually patch if you think that it's necessary.
I have to add that for me, testing definitely breaks stuff sometimes. Nothing beyond my ability to fix, though. Nothing beyond anyone's ability now that AI is around.
I believe I need to reiterate: Stable is for servers, testing is for desktops if you're not directly exposed to internet.
Again. Stable is for servers, testing is for personal use.
I never argued otherwise, ever.