I just got a Trezor Safe 3 and set it up last night. For the backup method, I chose the default selection of Shamir single share (20 words). However, I've been thinking about it and I'm wondering if there is any advantage of using Shamir single share vs the legacy method? I don't intend to upgrade to Shamir multi-share later and I know the biggest advantage of the Shamir method is being able to break up the seed into multiple shares that you can distribute, but I don't really want to do that. This being the case, is there any advantage of sticking with Shamir single share vs the legacy 12 or 24 word method?
This new Shamir or SLIP39 is much more secure because there is no signle point of failure, this is the biggest risk with using standard 12/24 seed phrase.
I see more wallets are adopting SLIP39 (Electrum, Blue Wallet, etc) and I think this is going to be used by everyone in future.
There is nothing wrong with old format and you can continue using it if you want, 12 words is enough and you can passphrases later.
You can find more information about SLIP39 here:
https://content.trezor.io/slip39https://docs.trezor.io/trezor-firmware/core/misc/slip0039.html