IPv6 fixes a lot of problems. It's actually a simpler protocol. It eliminates the need for NAT, which is a major headache when building networks. The security model is just traffic filtering. That's all you need.

It's got built-in privacy extensions. Most desktop machines make outgoing connections with an address that cannot listen on a socket. You cannot get portscanned by anyone you connect to. This is a problem that cannot be solved on IPv4. To make it better, the outgoing address changes about once a day (typically). This prevents web servers from following you around and building a profile.

Address scanning is a huge problem in IPv4. If you open SSH port 22 on a public server, there will be bots guessing the password within the hour. IPv6 space cannot be scanned like that, so it simply doesn't happen.

My personal hot take: If global IPv4 were turned off tomorrow, we'd migrate to IPv6 in a month and never look back. 90% of the pain of IPv6 is the duplication of work because IPv4 still exists.