Passing the keys along is a viable solution. There are a few reasons why I think BTCapsule is a better solution.

How do you plan to pass the keys down to your children? Most people don’t give their children access to their bank account before they pass away. This also opens up a single point of failure, because now you are not the only person responsible for keeping your keys a secret.

Do you lock up your keys in a safe or something that is password protected? Now your children must know and remember the password. If they forget, the Bitcoin is gone forever. If they write it down, then your back to trusting someone else with the responsibility of securing your Bitcoin.

You can leave it in a will, but now you are trusting a third party to ensure your children get the Bitcoin. If Bitcoin becomes illegal or the company you trusted is corrupted, there can be legal issues.

With BTCapsule, there are no passwords or third parties. The date you choose is the password, and the blockchain will not accept the transaction until the date has passed. If your child loses their wallet before your death, you can simply create a new one. This will make the old wallet invalid, so if someone else finds it or steals it, they cannot have access to your Bitcoin.

These are a few reasons. I’m sure there are more, but they’re not popping into my head at the moment.