The value of being able to see the deleted posts is so you can recognize the posters or their telltale phrases in future:
a) Too-good-to-be-true accommodation listings on CL/FB listing artificially low weekly/month-to-month rates on nice-looking properties, in order to "acquire" unwitting customers for marketing RE or 12+ month leases to. RedFin and/or their affiliates seemed to be doing a huge amount of this throughout 2022.
b) Deposit scammers on CL, FB advertising properties for which they are not the landlord; meet in person to pretend to take application and deposit. (Someone I know was scammed $1400. Obviously be skeptical, check owner, never give cash to strangers - but this still happens).
c) Another telltale is when the identity of the "apply to" URL is disguised using shorteners (or rendered as image).
d) Nuisance landlord(/roommate) scammers on CL/FB who repeatedly post a similar generic ad under different names/ addresses/ userids; then don't know which property in which country you're responding to, won't reply by phone, are in a different timezone/country, and insist you fill in their third-party application form incl. your contacts and SSN.