Does read-only index option really affect the performace?

Elastic Stack Elasticsearch
1

Does read-only option really affect the performace? If yes, how? If not why?
My scenario is this:
I've daily indexes with lots of documets (from 5/10 to 100 GB per day, it depens). If each day I make the indexes of yesterday read-only (I'll never write to them) is or not a good practice? Will I notice any optimizations?

2

There is no difference in terms of resources or performance when you mark an index as read-only. If you do not search those indices frequently, you might close or freeze them to save resources.