The problem with this type of motivation is as follows:
1 - Paying a lawyer is expensive, and maintaining one long-term is also very expensive. For example, if a person wants a lawyer to handle their will until they die, then every month that person will be paying the lawyer a salary. If that person doesn't pay the lawyer a monthly salary and only makes the will, who will inherit the will? If they give it to a trusted person, then they could create some kind of scam and keep the money.
Payment for the lawyer is expensive and painful for financial budget but the risk is not only about money.
It is risk with the laywer's actions in the future. He she is a lawyer, that's good but you can not completely trust any person with your private keys because they can turn evil and steal your bitcoins or your children's inherited bitcoins.
With Bitcoin, it is simple, only private keys are enough to move the fund, and it's unlike selling a real estate, an asset that can need the owner signature.
If something to do, I would like to do a little bit complicated thing like splitting private keys and custom words such as private keys hold by the lawyer, custom words are known by the children or family. It can avoid risk from the lawyer but it's complex idea and still cost expensive payment to the lawyer that in my opinion is not worth to spend.