Edit: mine was actually (partially) better because it assigned a short PIN instead of a full link, which meant you could just look at it and remember it for typing-in, instead of requiring a separate channel to "send" the link.
That's basically a hello world project. As you found out, the hard part is everything else, like funding it.
Honestly half of why I took it down is nobody was really using it. I didn't work terribly hard to market it, as I had no aspirations of getting rich and it would've been tenuous to monetize at all. I just told friends about it, etc.
I didn't imply there was a "hard part" to it. Just a neat idea. No need to dump on it.
About 15 years ago, my sites were pushing 400-600mb/s non stop. Nowadays, I barely hit 1% of my network cap at each VPS location.
It was called "Catch"
The motivating case was when you're in physical proximity to the destination device, but don't have any account linkage between the two (not even messaging/email/social accounts that are connected). The original idea came from university computer labs: transferring homework between the lab computer and a personal one was a pain. I had to sign into dropbox in the browser (and 2FA), or attach it to an email, or carry around a flash drive (which wouldn't work on phones), or whatnot. Just to move the file three feet. A glanceable code with no sign-in bridged that gap.
Other use-cases include people you don't know very well (and therefore don't have an email, phone number, etc.). We demonstrated the prototype to a crowd by uploading a file with the code visible on the projector, and suddenly everyone in the crowd had the file. That was pretty cool.