If you don't care about anything, you might as well have CGNAT. If you care, it's easy to see what XS4ALL does better: you don't get a locked down xperiabox, you get ipv6, you get good customer support, you get to set your reverse dns, you can set a carrier grade firewall if you want... I don't know how you can say that it's no different. It's different in the same way that a $4000 or a $400k car will both get you to your destination, but one has a lot more features than the other.
You can get IPv6 with Ziggo; it will utilize CGNAT. Its terrible. Things such as connecting over LTE to IPv6 OpenSSH won't work if the LTE is IPv4 only. Things like P2P (BitTorrent) or PlayStation won't work. For a proper networking connection you need either dual stack or IPv4. If you get such a router from Ziggo call them up and tell them you want/need IPv4.
I did that and they told me I had to give up v6 for that, so I noped out of that one. I'd rather have the new protocol than be stuck with the old one. If I need a v4 address (which I did to host a game, I was amazed ziggo pulls this on people and they're not required to have huge warning signs like "you're not really getting a normal Internet connection, you're gonna share an IP address with a million people and not be able to use it in the expected way") I'll do ssh forwarding (-R) to my box at XS4ALL.
Yes, Ziggo don't provide dual stack. It is either IPv4-only or IPv6 with CGNAT for IPv4. I'll take IPv4 in that case, wait till the rest of the world has either dual stack or IPv4, and then once the whole world has IPv6 I'll be OK with IPv6-only.
Why would we care if it's only historic events? We'd have moved to another isp and not bothered with a petition.