HTTP/2 Supports multiplexing, so you can send multiple requests at once on the same connection

Doesn't seem redundant to me. Even if you can multiplex requests, batches still have certain advantages, e.g.

- compression is often more efficient with larger payloads

- can reduce per-request overheads, e.g. do authentication once rather than X times

- easier to coalesce multiple queries, e.g. merge similar requests to enable data retrieval via a bulk query, instead of X individual queries

It isn't.

Batching means combining multiple logical operations in a single physical request. HTTP/2 muxes N logical requests over 1 physical connection, which is good, but the application will still process requests independently. You always want to batch workloads into single requests if you can, HTTP/2 doesn't change this.