I think it's just some kind of design trend or something. But I don't know anyone who isn't at least a little bit put off by it from a user perspective.

French has the added difficulty of requiring to choose between "tu" and "vous" if you want to use the "your..." style. So you can instantly see if the website is trying to fake being your friend.

I think Flemish websites just use "jouw whatever" but it's much less direct and jarring than being called "tu" in French by a corporate entity (not a native Dutch speaker though, but I've been living in Flanders for quite a while now).