Back in the days of 8-bit (and, to a lesser extent, 16-bit) console games, the prohibitive cost of memory prevented many games from allowing players to save their progress between sessions. As a wordaround, developers instituted passwords that a player could enter and pick up the game where they left off. The password is usually comprised of various alphanumeric characters which, through an internal algorithm, correspond to some factor of the game's state. The more complicated the game, the more longer the password. Because of this, games like RPGs could theoretically use a Password save system, but in practice it would be so long that it would be impractical.
With technology like memory cards and built-in hard drives in consoles having been the norm since the late 1990s, Password saves have since fallen out of favor. Despite these factors Passwords still made appearances in some, albeit few, newer games. These games usually don't use Passwords for saving games per say but rather for items exchanges. However with online connectivity now the norm, even these have become a relic of a bygone era.