And if you don't tell them what it is or where your encrypted seed is located, then how will they recover it after your death? Either you tell them your whole set up, in which case you are trusting them just like I trust my wife, or you don't tell them the set up, in which case you run the risk of them never being able to recover your coins.
If you don't have a family member you can trust, then there are trustless ways to set up inheritance, such as by using timelocked transactions. This is a better solution than giving out passwords in envelopes.
You just need to tell your wife where is located your encrypted seed, then she will be able to access your encrypted seed but not being able to decrypt it while your relatives will be able to access your password (if they unseal the envelope at least) but not being able to locate your encrypted seed.
AFAIK you can't spend anymore funds included in a timelocked transaction before its expiry date once your timelocked transaction has been mined. In addition, it implies to know at which date you will die. That's not convenient at all.
Leak it over the entire internet, as they've done with plenty of data in the past? Store it in plaintext, as they were caught doing with users' passwords for 14 years? Or maybe just shut down the service you are relying on, meaning your data is lost forever.
You can check the service from time to time before losing your memory or dying, if you are afraid of that.
Because she is not an idiot. If she is at risk of falling to such a low level scam, then so is everyone on this forum and nobody's bitcoin is safe. Not to mention that it would be significantly more difficult and time consuming for her to collect all the necessary back ups to start emptying various bitcoin wallets than it would be to log in to a fiat account and empty it out.
Yes I think nobody is safe with his Bitcoin funds, even you, because obviously other people than you have plain access to your funds. That's disappointing, but we have to admit that Bitcoin is risky for everybody.
You can simply encrypt your seed with a password (or use a split seed) and write this password in your will left at a notary
True, and that's a good system for someone who does not have anyone they can trust. But if you do have someone you can trust, you don't need to do this. It also doesn't help very much in the situation where I suffer memory problems but am still very much alive, which happens to literally millions of people a year, and can be a very long and complex process to gain access to the assets of someone who is still alive.
AFAIK most countries laws allow people to update and modify their will, so you would certainly be able to make a codicil and thus to read your own will, even if you have lost your memory actually.