As a hobby project or creative exercise it's interesting. I've thought a few times about trying my hand at it. One could really geek out on some ideas and have fun with the building process.
Practically, it has some drawbacks as noted. Oddly, for me it's not weight or aero - I can see ways around that. Mostly I see the width being an issue for traditional road touring as there are so many times a wide trailer would be sub optimal in terms of shoulders, guard rails or rumble strips. But if the right road or trail system were available it would be a novel, though slow, experience. Certainly a conversation starter.