As others have mentioned, it’s simple things takes alot time finding/figuring out.
I use GIMP within Ubuntu MATE few times a week to edit pictures. Simple edits nothing major.
One of the thing I need regularly is to highlight certain part of the picture.
Now in Microsoft Paint I can draw a rectangle, choose its border thickness, and color in 2 seconds.
I have learned how to do the same in GIMP few times but it took alot of time and I still forgets after few weeks.
So now I just reboot the PC and log into Windows or use Windows virtual machine and draw rectangle in 2 seconds in Microsoft Paint.
Mine is extremely simple use case, so I can only guess how difficult or how time consuming it would be for actual professional to create artistic work in GIMP vs Photoshop (or in similar commercial software).
Just my 2 cents.
Well, there is no native .deb package and “There is no plan for official .deb pkg”.
Source:
https://github.com/zen-browser/desktop/issues/328