Quote from: bitcoin_user on Today at 06:24:45 AM

If I have a seed in addition to a 2-of-3 vault, it would be like a 2-of-4 in a sense, wouldn't it? That is: with a seed, it's as if you had the original wallet.

Setting up a multisignature wallet isn't a substitute for your seed phrase, even if you use a multisig set up you must back up your seed phrase(s) appropriately. A 2 of 3 multisig wallet simply means two keys out of 3 are required to spend the funds from your wallet, it does not mean you won't back up the keys and the seed phrases to all of them.

Quote from: bitcoin_user on Today at 06:24:45 AM

But it's also another complication since I need to find where to hide this seed. And I think it's already quite difficult to manage the 3 different locations with the 2-of-3 multisig.

That is one of the disadvantages of multisignature wallets to single signature wallets, you have more backups to manage and keep very safe, in different locations.

Quote from: bitcoin_user on Today at 06:24:45 AM

The desktop can get a virus and be stolen, as well as the mobile phone. But what probability is that both of them get stolen or get a virus/keylogger at the same time (and combine to get the 2-of-3)?

The probability is very low, and that is the advantage of a multisig set up, more security from possible theft of your BTC, but multisig comes with more responsibility when it comes to backing up more things, and someone who does not have enough knowledge should start with a single signature wallet, and advance to a multisig wallet when they understand everything about storing their BTC in a safe enviroment.