What is the purpose of helm delete --purge

Using helm is super cool, but what is the purpose of using helm delete --purge

I can see the doc says:remove the release from the store and make its name free for later use

So what is the purpose of saving the name and not releasing it with helm delete?

When you do helm delete $RELEASE_NAME it deletes all resources but keeps the record with $RELEASE_NAME in case you want to rollback. You can see removed releases via helm ls -a. Whereas helm delete --purge $RELEASE_NAME removes records and make that name free to be reused for another installation.

Just to note as of helm v3 --purge is default behaviour. You no longer need the flag

If you want to keep any history (aka the behaviour of helm 2.x's helm delete without the --purge flag) you now need to use --keep-history eg helm delete nginx-ingress --keep-history