Daedalus Reason for 24 BIP39 Words - it would take 3,830,854 years to crack?

I’m looking at a website which allows the creation of a random list of BIP-39 words, https://iancoleman.io

Per the website if you use a 2 of 3 BIP39 Split Mnemonic scheme, wherein someone would only have 16 of the 24 words, the website says that it would take 3,830,854 years to find the correct missing seed words. Is this why the Daedalus team chose 24 words so that it could naturally support the 2 of 3 BIP39 Split Mnemonic scheme?

Would using this site enable me to create a Cardano valid set of words? Is there a way to create a set of 24 Daedalus Compliant words without being connected to Daedalus?

Edit: Just tested. I was able to restore a 24 word wallet on Daedalus using random words generated from https://iancoleman.io/bip39/

Yes, any BIP39 compatible mnemonics (as in your case created using generator) will generate a valid key and thus, equate to a wallet.

No as far as I know.

The 24-word means 256 bit entropy, while 12-word is 128 bit entropy, so a 15-word would be enough for achieving the 128 bits of security that EdDSA (especially the used Ed25519) offers (a little bit less than 128bits security).

I think the main reason was using the 256 bit entropies (i.e. 24-word length mnemonics) is supporting multi signatures, which theoretically can loose half of their bits of the security.

So, I think mutlisigs based on 24-word entropies can achieve the expected 128bit security of EdDSA, but it seems to me a bit contradict, as the normal keys (which will be used as pub keys required for mutlisig) based on that highest entropy would still only achieve 128bits security, so it’s not clear for me.

But, to tell the truth I have not dig deep into it.