UUIDv7 interoperates with all the other versions of UUID. The v7 support in Postgres doesn't add a new column type, it makes the existing column type more powerful/capable. Applications that had been using UUIDv4 everywhere can get cheap Snowflake-like benefits in existing code just from switching the generator function. Most languages have a GUID or UUID class/struct that is compatibly upgradable from v4 to v7, too.