Seeing the point on UI/UX got me curious as well and from a brief look I don't quite see where it is coming from, but maybe they will expand on it. Regarding their point about relatives loving Google/Kagi for usability: If you don't already do that, I believe it can be pretty eye-opening to just place some "tech-illiterate" person in front of your product and check if/where they struggle. There were lots of situations where I saw people struggling with steps I stopped thinking about, just because I was more familiar with the software. And while I have nothing to do with UI/UX myself, I am pretty sure that kind of paper cut is what tends to block any kind of broad adoption.