There were several internal reasons why Microsoft transitioned its Edge browser to Google's Chromium web rendering ecosystem. However, there were also some clear benefits to users, such as an improved browsing experience. Furthermore, Microsoft Edge can also benefit from Chrome's extensive catalog of web extensions (Addons).
That is certainly a benefit that has quickly proved itself and developers seem to be taking notice. Indeed, there are now 1,200 extensions in the Edge Addons Store. It is worth noting this does not mean the number of Chrome extensions available (more on that shortly), but rather the number of dedicated Addons.
In other words, this is the number of Addons developers have created to run specifically on Microsoft Edge. Sure, that's still way lower than the extensions on Chrome and Addons on Mozilla Firefox. Although, it shows developers are more interested in developing for Edge than they previously were.
Another important point to consider is that users can still install just about every extension available from Chrome. That said, when visiting Chrome's Web Store from Edge, you'll be greeted with this message:
“Google recommends switching to Chrome to use extensions securely”.
Does it Matter?
Many security researchers think Edge provides the same level of security as Chrome, but naturally Google would prefer people use its browser. As for Microsoft, it would prefer its Edge users not having to see the message. The only way to do that is to get as many of the Chrome extensions available directly in the Edge store.
It's arguable that none of these matters for the end user, who get the extension they want on the browser they want regardless.