Play-by-Post can be an interesting medium for favoring narrative over advancement. Even advancement-heavy systems tend to move too slowly in PbP for advancement to take focus over the emerging narrative of the game. The written nature of the game often encourages deeper characterization and other literary elements like establishing setting, pace, and backdrop. While I do both, I find Play-by-Post to be the more rewarding experience for roleplay that embraces narrative, though face-to-face (or video chat) gaming with RL friends/acquaintances is more socially rewarding.