Yes I do get the general argument for CD (though I have issues with how universally it can be applied based on the sort of BVT I've had to do for SaaS platforms I worked on in the past, where it just wasn't possible to safely release new versions of key components without needing several days' worth of testing, most of which was waiting for verification that interactions with banks etc. had worked as expected).
Agreed, like almost everything it’s not universally applicable.
If you have external contracts that are onerous to validate then it can be quite expensive to build high-fidelity internal representations of those contracts. Could still be ROI positive to do so!
In most cases the contracts are either internal or simple (non-temporal) external contracts like a REST API, so most orgs benefit from moving in this direction.