There's a bunch of advantages. IPv6 can be useful since your devices can have the same IP both internally and externally. No dealing with port forwarding. No split horizon DNS (where you have different DNS entries for internal vs external). No NAT. No DHCP required for client systems (can just use SLAAC to auto-generate addresses). Much simpler routing. It's a bit faster. Proper QoS.
I used to use Comcast, who actually have very good IPv6 support. They were the first major US ISP to roll out IPv6 to everyone, around 10 years ago. Unfortunately my current ISP doesn't have IPv6, but they're aiming to roll it out this year.