https://packages.ubuntu.com/focal/chromium-browser
In previous versions of ubuntu, that package would install chromium, as one would expect.
In recent versions of ubuntu, this package is a stub that installs snapd, and then snapd installs chromium.
There is a substantial difference between those two things. Users that try to install chromium through an open package management system are being pushed to Canonical's proprietary store.
> The problem was the decision to change the Ubuntu chromium-browser APT package itself upstream in Ubuntu. Previously, that package would simply install Chromium directly. With the change, it would instead install the Snap package-management tools first and then install the Snap equivalent of the Chromium package — without making it clear to the user what was happening.
I just use the Chrome apt repository from Google which seems simpler all around.
https://ubuntu.com/blog/chromium-in-ubuntu-deb-to-snap-trans...
Canonical couldn't afford the maintenance costs for it. On Ubuntu distributions it's either the snap or you have to create some weird frankendeb aspect by pulling from Debian.
They explained it better than I would.
In other cases, I don't think of a case where apt installs snaps over apt. I think the only priority for the decision choice was based on most recent version. Although this aspect I am slightly unclear.