Or Patroni (https://github.com/zalando/patroni), a better option. But it is complex to setup, requires other external tools too (DNS, virtual IPs, Envoy proxy, etc) and none of that is included in Postgres.

Postgres HA is far from easy. I gave a talk 2 years ago about this (video and slides: https://aht.es/#talks-modern_postgresql_high_availability). This is an operational disadvantage.