Which means if the other key with the wallet owner is lost, the hot key can be used to recover the coins while the key with Casa is not online?
I do not like the idea of services with inheritance purposes. Bitcoin developers have made everything possible by holders but they just need to read and learn about them and choose their own choice. Inheritance purpose services are not necessary.
If any of the keys you hold (as an owner) gets lost, then you need to use your other key and casa's key to unlock your funds. There is a waiting period however, to make sure that you 're not abducted or in danger or that nobody tries to imitate you to steal your funds from casa.