They have controls as most of these folks have to have (background checks, access controls, physical security, etc [1]). Still better than randos pulling your mail out of the mailbox in front of your residence imho. Its a shim until the last of need for paper mail gets deprecated, as I still need to receive correspondence of importance via snail mail (business filings, IRS, etc).

[1] https://www.sbimailservice.com/security/

(all commercial mail processors you consider should have similar controls in place, make sure you ask!)