Though I have seen a few instances of it happening, I don't see a widespread lack of square checkboxes. I think he's cherry-picking. But then I spend more time

Though I have seen a few instances of it happening, I don't see a widespread lack of square checkboxes. I think he's cherry-picking. But then I spend more time on the web than in mobile. In general, I'm not worried about this. To the extent that it is confusing to users, and to the extent that confusion causes problems, it will be corrected in time. Nobody is incentivized to have bad UI if it costs them money. People on HN seem to think designers run everything, and that they spend most of the day trying to make things harder for users (out of native malice, or because it makes them feel smart). The reality is that in most places, designers actually want things to be better, and product choices are driven exclusively by money made by users successfully using your app. "We can't fix our bad UI because it will make our designers angry" is not something I have ever heard said at any company I've worked for.