The gloves are fashion-gloves, like the dress, not to be worn into dungeons.  Gloves that let you disable traps with no loss of dexterity are a higher tier of adventuring gear than this outfit belongs to.  Bella could in principle wear the dress but not the gloves; it would look slightly odd but not in a standout way.  She could also wear neither the dress nor the gloves, but then she'll look more like an Adventurer attending school, and less like a platinum-tier wealthy sorceress with an intended profession that requires her to visit dungeons to level her Skills.

The gloves are fashion-gloves, like the overskirt, not to be worn into dungeons.  Gloves that let you disable traps with no loss of dexterity are a higher tier of adventuring gear than this outfit belongs to.  Bella could in principle wear the skirt but not the gloves; it would look slightly odd but not in a standout way.  She could also wear neither the skirt nor the gloves, but then she'll look more like an Adventurer attending school, and less like a platinum-tier wealthy sorceress with an intended profession that requires her to visit dungeons to level her Skills.