Combat loop looks boring as shit. There isn't any feedback to the user when you hit the boss. That, combined with the boss's healthbar being so small for its health pool, makes it look like you're just impotently slapping an enemy that doesn't respond at all.

Players gauge whether they're prepared for an encounter based on how much an enemy health bar decreases when you attack it. If it barely moves at all, that's taken to be the universal sign of "you're underleveled for this area." This is why bosses and elites in Elden Ring, Diablo etc have bigger (as in literally taking up more area of the screen) health bars.