I think the fundamental use case, and who the users of this type of product would be, is largely missed in this discussion thread, so far.

These third-party, collaborative, multi-sig solutions, that feature Inheritance plans (like Casa, Nunchuk, Unchained, etc), are primarily for less technically-savvy Bitcoin HODLers (unlike those on Stacker News who largely understand Bitcoin).

While the primary HODLer themselves may be able to intelligently protect and access their Bitcoin, their heirs may be clueless. So instead of risking loss, these third-parties offer a way to pass on the Bitcoin via solutions that are very easy to execute by the less tech-savvy heirs.

And, they are 2-of-3 so the custody partner never relinquishes control to the third party.

While nothing is perfect, it seems these companies understand their customers want to mitigate counter-party risk, while also giving their heirs an easy way to access their Bitcoin upon their demise.