I like your take, but if your title had been “GUIs are integral for linux adoption and devs should prioritize it more often” it might have gone over better.
Ffmpeg is one tool that I love and want to recommend to other users to do simple and efficient video file conversions/cropping/trimming. But the lack of a GUI doesnt make it easy. Luckily I have found GUI wrappers on windows and linux, but without those I would absolutely not recommend it. Youtube dl is another example of this. Im glad there are other open source projects providing GUI wrappers for these scenarios.