Yes, @Yoann Rodière, It has been fixed by https://hibernate.atlassian.net/browse/HSEARCH-3424.

Where all numeric types:

• java.lang.Byte
• java.lang.Short
• java.lang.Double
• java.lang.Float
  are passed as they are to the backend API.

Elasticsearch backend supports all of them natively, we use all of them.
In Lucene we uses IntPoint for byte and short, DoublePoint for Double and FloatPoint for float.

We need to add some tests to probe the effective type used by the backend. Currently we probe only the behaviour.