I notice importance is usually a quality stressed when supporting a character one already wants. Especially if their case is otherwise a little light.
Like, Dante doesn't need his importance to the character-action genre spelled out because all you need to say is that the character is popular both generally and within the fanbase and DMC is a big, successful series. Those two points are worth enough. And actually matter. Same with Doom Slayer and the FPS.
No one's up in here talking about the importance of games/series like Ultima, Virtua Fighter, DotA, GTA, WoW, the Sims, Tamagotchi, Harvest Moon, Space Harrier, StarCraft, Shenmue, etc, or, frankly, rarely even Dark Souls and Fortnite.
The important **** is popularity (generally and/or in the fanbase) and the size (success-wise, not title-wise) and prevalence of the series (ideally in all crucial regions). Importance can lead to those qualities but, for Smash, it itself is less... important.