300 bits of entropy for a passphrase is massive. That's equivalent to 28 bip39 words! And this is on top of the maximum of 256 bits provided by the seed phrase. That's a lot to type in.
Discussion
Yea seems excessive
Here's where the magic happens. I use keepass, and let it create a high entropy passphrase for me. Then I let keepass type the passphrase in for me.
Everyone says don't inter your seed phrase online, and I agree. I only enter my passphrase online. And keepass has a number of settings to circumvent key loggers.
But let's face it. If by some miracle someone spoofed my passphrase. They still need my seed phrase. The likelihood of getting both is slimming and none, and slim has left the building..๐ป๐๐งก๐ค ๐ฝ