As a normal user: why do I need IPv6?

As far as I know, the majority of websites (about 70%) do not support IPv6.

Depends on your ISP. If you live in a place where there aren't many IPv4 addresses available, CGNAT is the reason you're seeing a lot of Cloudflare/Akamai/Google CAPTCHAs everywhere, and IPv6 fixes that.

same reasons northern europeans had to invent all sorts of fancy food preservation and complex power struggle societies revolving around crop limitations and war.

Meanwhile closer to the equator, much less progress was needed to live and let live.

In short, Americans are native tribes. we have plentiful IPV4 and couldnt care less about SLAAC or whatever other complex moon sun and seasonal tide gods, salted codfish and salt mining operations. we just dont need to care about long addresses, they're plentiful here.

You need it because there aren’t enough IPv4.

If you have a mobile device with data, you’re likely already using it.

Do we really need all the mobile phones and IoT devices of the world to be publicly addressable? Is that even a good thing?

If you want to use the internet, you need an IP address.

You can share that IP address by putting multiple hosts on the same local network and using parts of the transport later. NAT was invented because of lacking enough addresses.

CGNAT is a guarantee that you have plausible deniability on the internet. NAT is also a guarantee that you are not addressable from the internet.

It’s a feature.

I don’t think that’s true. But of course it depends how you’re measure the majority of websites.

Most of the figures I see show 60-70% of the top 100 sites do support it. But maybe that does not reflect your usage.

Why do you need it? Maybe you don’t right now since ipv6 only sites are niche. The most tangible advantage I’ve seen is avoiding CGNAT. Gamers in particular don’t like that because it introduces latency. Services like Xbox live definitely do support ipv6 for this reason.