I'm not convinced on multi-chains, sure I can see private chains and chains for games or things like that but that's just going back to equity investing with extra steps.
As for something that's going to be global money I can't see how multi-chains all in different codebases, different developers all of which cannot enforce rules on another don't fall apart completely. Everytime you add a connection with another chain you multiply the attack surface
Code is not law if it's not protected by multiple nodes, and since most chains code is run on centralised servers they can always be attacked from one or other end. There's a lot of overpromising going on in the "we've got better tech" space. I've yet to see anyone really deliver