Note this must remain an option, because Elasticsearch nodes may not be able to accept GZIP compressed requests, or users may disable it. See https://www.elastic.co/guide/en/elasticsearch/reference/5.5/modules-http.html

We would need to test it first in a real network environment (i.e. not with the Hibernate Search application and Elasticsearch node on the same machine). If this does improve performance, it may be worth it.