But that's besides the point. CLIs in itself are harder to use than GUI and the entire FOSS ecosystem biases itself towards CLI. So that in itself is a marker for inferior usability.
With training a CLI can be made superior in many aspects to a GUI. But it takes training and mostly only people in IT are willing to go through this training. Overall from a common users' standpoint, GUIs are superior.
If you want to branch out to less popular DEs then of course you should be prepared for it being less polished, but does any Linux newbie really expect dozens of super polished DEs?
This is muscle memory. No shortcuts are not an alternative, merely a workaround. The underlying issue would still be there.
Unfortunately Android has taken over this inconsistency, probably because there is nobody that enforces it. "Mark as read" and "Reply" in the notifications are sometimes left/right, sometimes reversed. Yes/no questions are sometimes left, sometimes right. Snooze vs. alarm cancel too. What a disaster.
CLI? Absolutely.
Desktop interfaces are an inconsistent mess.