What's the point?

You still have to share the link somewhere, why not just share a block of text (invitation, campaign, whatever) directly instead?

Yes! It's similar to people sharing a simple url within a QR code only. I find it insulting and inconvenient - i can remember or jot down and type in a url - i don't need a smartphone to do that. In theory you could put a small html/website in a dense QR code, that would be truly offline - it's a similar thing.

There are also the Pico-8 cardridge format, where a game is stenographically embedded in a PNG https://github.com/l0kod/PX8

And the Piet and Pikt esolanguages where the visuals are the code: https://esolangs.org/wiki/Piet https://github.com/iamgio/pikt

Oh, yeah! Its not will get indexed by search engines as well.

I think its just for fun :)