Mount&Blade games in general are more about the overall experience than whatever awaits at the "finish line" -because there is no finish line.
The franchise has always had one of the most unique and intuitive combat systems out there, and it's probably the most enjoyable part of the game. It's endlessly fun to fight in tournaments and battles (from small-scale bandit skirmishes to massive field battles and sieges). Plus, the sheer variety of ways you can do combat -from cavalry with lance, cavalry with sabre/2H weapons, horse archer, infantry with sword and board, infantry with 2H/polearm, a skirmisher light inf with throwing weapons, archer, and crossbowman, means there's almost endless replayability.
The roleplay aspect of the game is another big draw. The whole journey from complete nobody to lord/ruler plays out like an adventure narrative in and unto itself, and takes a unique path almost every different playthrough. Because the world is so fluid and dynamic (and a little random at times) you never play the same game twice. Your character directly meets many of the NPCs they interact with while roaming around in settlements: taverns (companions and mercs), the streets (people of interest/business opportunities/notables), and the great halls/keeps (lords), making for a personalized and immersive experience.
Alternative approaches to the traditional warlord playthrough also exist, like being a merchant or notorious bandit outlaw. This, much like the many options you have for combat, adds a lot of variety and replayability to the game. This is why when Taleworlds announced Bannerlord was going to have an organized crime element inside of settlements with black markets, street gangs, and gang wars, I got very excited, because it would have meant even more options for unique and alternative playthroughs, but alas...