During the 3rd and to a lesser extent the 4th generation of home consoles, before the proliferation of inexpensive, non-volatile memory, passwords were a popular alternative to saving data.

I don't think James(AVGN) was exaggerating when he complained about the length of games' passwords. Castlevania II: Simon's Quest's designers might have been able to justify the game's long alpha-numeric passwords as inventory, exp and other player information was stored.

However, many other games would only use the password to access stages. I don't see why designers of said games felt it necessary to create alpha-numeric gibberish passwords exceeding 10 characters in length. Inputting large passwords was often time consuming, especially when they had to be redundantly inputted again after a game over.

I think that a four digit hex password (0-9, A-F) would have been sufficient. If security was the justification I think that 65,535 possible combinations is more than enough. If a human was to attempt to crack the passwords using brute force, even if there were 100 valid passwords, a 1 in 65,435 chance of success would still be very secure.