Yet HN never misses the opportunity to dogpile on anyone who points this out: data trasfer costs, battery usage, jokes about the Silicon Valley sitcom.
As if most phones weren't connected to wifi and power for 10+ hours a day.
I don't know of a single US mobile network that provides publicly addressable IP space, v4 or v6, it's all behind more than one layer of NAT.
AT&T doesn't even allow direct internet access, every single connection goes through their horrendously bad transparent proxy that breaks TLS 1.3, breaks ESNI, causes a SSL_RX_RECORD_TOO_LONG connection reset if you negotiate only modern ciphers, and sits in the middle of every connection to prevent things like obfsproxy.