The reason for ILM for me it to roll over the indices which are for example having more than specific number of docs to another index with fewer shards, and after a few months, I want to delete them... However, I need to keep each day log into a separate index.
If you see also this:
https://discuss.elastic.co/t/index-lifecycle-dilemma/177598
he wants to do the same thing, but for me it does not work.