> On mobile this is a strong contender for the worst UX I've ever seen.

Pretty hyperbolic. First of all, this is a human and their work you’re talking about. A little respect goes a long way. Secondly, if this is the worst UX you’ve ever seen on mobile, I have to assume you’ve only been using the internet for the past week or so. This experience worked great for me on mobile Safari with no instructions required. You can’t say that for a lot of mobile UX including, I might add, Safari itself.