firefox probably has cookies whitelist facility. (I don't know because I use Cookiebro add-on, which is very nice [simple, easy], lets me see and control.
If your default setting is block cookies and you do not whitelist ASR, you will have to log in manually each time [instead of Firefox doing it automatically] and New Posts search will not work. That last is one of the proper reasons for cookies, vs. tracking for ad purposes.
I use Cookiebro [authorised/approved add-on], continued to use it since Firefox began doing cookie control, because it is easier - I know what's going on, and don't have to deal with Firefox settings menu/UI.
PS: My daily routine [re this] is start Firefox...then click the Cookiesbro button and clear the session cookies. (Which could be done automatically, is one of the options/setting at the top of the page, can also be set to clear them periodically [30 minutes, 60, etc.]) Blacklisted and non-white-listed cookies were automatically cleared as part of startup process.