Let's say a manual & auto-run filter on incoming email named Filter exists (in my case, known spam senders, which are sent to folder called Folder). After fetching pop3 mail so new/unknown/unfiltered spam senders are now listed in the incoming folder named Inbox (after automatic application of Filter on already known spammers sent to Folder), with some messages still in Inbox which are automatically flagged as fire-icon-labeled-junk messages, I will unflag the messages I deem valid which I wish to read later, and can select amongst the still-flagged messages those I deem spam (typically at this point, Sort by Junk Status and group select).
Now, I'd like a single procedure to bulk-add the senders of selected messages to my already existing Filter, from the currently selected Inbox messages, after which I'd manually run Filter and see those messages dissapear into Folder. (Way faster than select one message at a time and ctrl-Create-new-filter on dozens of investor opportunity spams. Not sure why I even bother keeping that repetitious garbage in Folder..)
Ideally, I'd have an option to smart-add the new rule set : rather than have each spam message add in my match-any ruleset a rule labeled necessarily as "Spammer@Subdomain.domain.root", software would offer the following choice to generalise the source (and avoid simple harrasment loophole of swapping Spammer with Spammer2, or swapping Subdomain with Subdomain2). Either add rules as "@subdomain.domain.root" or even "domain.root". Unfortunately the practicality of this choice is case dependent, and I'd probably have to revisit the rule set to fine tune rule label choices on about 5% of the spam, but I hope you understand the usefulness of generalisation.