Co-signer vs co-applicant

I am looking at a single family RE loan and there is an applicant,co-applicant and two co-signers. I have never seen co-signers on a RE loan only co-applicants. Is this okay?

If they do not get a direct benefit. Could be parents co-signing for kids who have no/limited credit.
Cosignor rules do not apply to purchase of real property.

Thanks Southern Banker.