I think I misunderstood your initial toot. In retrospect I think you are looking for "use-case"s in which not showing line numbers are preferred, right? In that case: any time that grep output is piped elsewhere, especially with `-o` or `-v`.
I personally never have practically used grep with line numbers, perhaps because ripgrep is much more handy esp. by file type.
That said, I most of the time turn on Perl regex 😅
