Note while you have cosmetic similarities to ipv4 addresses, the actual challenging part of that is the packet format and various translations.
We actually have a number of existing schemes for ipv4 mapping onto larger address space and the attendant NAT requirements. The presentation of addresses in an ipv4 looking way is the least of the challenges.
So don't take IPv8 seriously, it is slop and even in theory it wouldn't add anything new except a different cosmetic look to raw addresses and shortening the address space for no good reason.
Basically people see an address like fdec:46f7:9b7f:1::3:20 and run screaming away about the complexity, seeing the address as a comprehensive indication of complexity, even though the real challenges lie underneath.
The whole 'traditional ipv4 just has 0.0.0.0' stuck in front of it is essentially exactly the same idea as, say 64:ff9b::142.251.152.119. Now there's also the likes of ffff::142.251.152.119 but that's just so software can pretend to speak IPv6 when the OS is really doing only IPv4. So they needed another prefix to indicate the network doing the v6 to v4 translation instead of the OS.
Anyway, the thing is that while it cosmetically looks more similar, it's not really solving the fundamental compatibility situation. It just "looks nicer" because it sticks to dotted decimals. However in practice, would fdec:46f7:9b7f:1::3:20 really be somehow less usable than, say, 120.30.204.78.167.144.120.209? The simple reality is that the 4 octet decimal pushed human usability enough as it was, and going to sufficient octets just brings it out of mere mortal reach. If you did want to say have more friendly local network addresses (the vast vast majority of human memorized IP addresses), then technically you could have fd::1, fd::2, fd::3, and those would all work and be super easy to remember (the ULA RFC says you are supposed to toss in 40 bits of random for good reason, but if you were using 10.0.0.1 style addresses, you would be no worse off with fd::1, fd::2, etc). You can even trivially have them live alongside 'real' global IP addresses, but ignore them whenever you want to just hand type a local IP address. You can even have something like a hex DNS. fd::f00d, fd::beef, fd::d00d, and so many more for your pleasure.
There's more features in IPv6 but you can ignore them since they are mostly for the machines to wrangle (the fe80:: addresses for example).