If you are in an enterprise environment, it is easier to sell Ubuntu - at least there is a company that can provide support for it behind. Companies want to make sure someone is on the hook to fix an issue that would be blocking to them, and this is much harder with something like Debian.

That’s why Red Hat is used that much in companies, and what Canonical main revenues are coming from.

But as a selfhoster, I use Debian by default for my servers. Only if there is a very specific need for Ubuntu would I switch, and I am frankly tired of the Snap shenanigans on my desktop (thinking of migrating to PopOS or KDE Neon).