What's the difference between doing

1. Seed phrase + passphrase number 10 (BIP 39)

Vs

2. Seed phrase + index 10 (BIP 84)

???

If they at the end of the day achieve the same thing which is generating a new wallet even though it results in different wallet, why do we need 2 BIP to achieve the same thing?

I don't get it. Can someone please help me understand?