Well she's a lot taller than she looks and can see past a lot of the stuff that the other gnomes and even dragons can't help be curious about and end up being caught up in. Perk of being neutral, long lived and guardian of the timeline. Chromie is a gnome because of their curious nature and love of exploration serving Chromie well for the role and task as well as the madness of letting it all be transient in order to do the job well. Endless possibilities and outcomes yet Chromie can't get attached to any of it without jeopardizing all of Azeroth.