Virtualbox installation source?

I am using Ubuntu Mate 18.04. I installed VirtualBox from Software Boutique just a few weeks ago and while installing I noticed that the installation source was (as it was when I installed VirtualBox a long while ago on Ubuntu Mate 16.04). The install that I did added the download virtualbox org repo to my system. However I just noticed today while browsing the Software Botique, that it seemed like VirtualBox is not installed on my system (there is a green "Install" button, when usually the installed apps have "reinstall", "remove" and "launch" buttons). But I actually have VirtualBox installed. I noticed the difference is that now the source on Software Botique for VirtualBox is "Ubuntu Repository".

Is there some reason for this change in the Software Botique source? Is there some problem with the download virtualbox org repo? Should I also remove the installed version and remove the added source and reinstall from the Ubtuntu Repo?

The source for VirtualBox did change last month:

@Wimpy would know the reason, but I presume it's to reduce reliance on sources outside of Ubuntu's archives, especially as Oracle give new package names for each major version. Or... it could be down to other reasons like package dependencies that were causing a problem in newer versions of Ubuntu.

Both builds use different package names (virtualbox-5.2 vs virtualbox-qt), which is why it's no longer showing up as "installed".

There is a slight graphical difference between the Ubuntu and Oracle's build of VirtualBox, but it's fine either way to continue using Oracle's build or switch to Ubuntu's.

Ok, thanks for the answer! That makes total sense: if there was some problem with how the Oracle version works with 19.04 for example, it would be best to use the Ubuntu repo as default source, since the version in there would be tested for that version of Ubuntu. In the Oracle repo it is the same version, no matter what version of Ubuntu is used.
I think I'll stick with the Oracle version for the time being, as it seems to work ok. Also I am interested in trying out the 6.0 version of VirtuaBox sometime, and I think using the Oracle repo is the only way to get that version.