Great question.

We address this in a few ways.

First, Nunchuk was built on open standards. BSMS is a BIP. It is actually a thin wrapper over Output Descriptors, invented by sipa and supported by many popular wallets such as Sparrow and Specter. We also support other wallet configuration formats, such as Coldcard or UR2. This means that you can easily recover wallets created in Nunchuk elsewhere. Here is an example recovery guide.

Secondly, our assisted wallets are all multisig wallets whereas Nunchuk the platform only holds one key, and the other keys are held by the user. That means the user always remains in full control of their funds.

Thirdly, regarding the inheritance planning aspect, we recommend users to use a rolling short timelock. This mitigates the risks of Nunchuk going out of business and also anything unfortunate that might happen to you.