[bushbaba]

Anycast can have serious reliability challenges. It was common at GCP for a small QPS user of anycast to have their Load Balancers nuked in a given pop as it was backed by a single machine. But BGP showed it as still the best route. The major DNS based offerings don't have such issues.

[kixelated]

QUIC has support for preferred address, where anycast is used for the QUIC handshake then the connection migrates to a unicast address. It still has issues but it's nice to have sticky established connections and avoid flapping mid connection.

[wbl]

I work for a CDN that does DNS steering. DNS record lifetimes are nonzero and can be surprisingly long. But you do get some very fine control over where data goes if resolvers cooperate.