No, i am not suggesting to create your password like this. you can create something like !Went>P@r!$&be$tmem0ryev_r
Something that you can create that reflect to your experience and easy to remember and hard to crack
And how is it easy to remember? If it's some sort of substitution scheme, like replacing O with 0, then it's easy to crack, if it's truly random (which can only be generated by some rng and not human mind), then it's really hard to memorize and you will forget it unless your repeat it multiple times per day every single day.
Compared to that, mnemonic seeds have guaranteed sufficient entropy and they are easy to remember because our brains are good at remembering natural words in sequences.
Don't you think it is easy to remember such password !Went>P@r!S-Be$tMem0ryEv_r
Well, you're right and wrong at the same time.
Right if you were referring to a traditional way of accessing "username" & "password" on servers, and the hackers can sense your way of creating password is like this.
But with Crypto, it is a different story. First, the hacker needs:
1- to figure out that the public key on blockchain belongs to YOU.
2- then he needs to figure out whether the public key was created based on BIP39 or legacy way (private key only per each public key).
3- then need to know that your way of creating passwords is like this.
You REALLY think it is easier to remember 12 random words (in order) THAN creating a strong password of your choice???
In terms of guaranteed sufficient entropy, you can your own and test it on
http://rumkin.com/tools/password/passchk.phpTest for example, !Went>P@r!S-Be$tMem0ryEv_r