Additional image stores doc clarification

[pczerkas]

man containers-storage.conf says
…
[storage.options]
additionalimagestores=[]
Paths to additional container image stores. Usually, these are read-only and stored on remote network shares.

But when I tried to mount read-only file system onto additional image store I got:
Jan 27 20:54:45 ip-10-0-0-132 crio[11928]: time="2023-01-27 20:54:45.100386900Z" level=fatal msg="validating root config: failed to get store to set defaults: creating locker directory: mkdir /var/lib/crio_store/overlay-images: read-only file system"

@haircommander suggested the doc needs clarificaion of what read-only means in this context.