It's not about delaying the transaction. If you only rely on CLTV, a spammer can mine a notarization transaction today and pretend that it has been published a long time ago.

But you are right, the software could additionally check that the notarization was mined N blocks before the locktime. This introduces an extra parameter, and it feels a bit like misusing CLTV, but it would indeed allow for longer time delays than CSV.