In the Witcher series, it's implied that the world of the story 'collides' with other dimensions over time, and each time it happens, new races and creatures get trapped inside. The very first, before elves, before Dwarves, were Gnomes.

They're like the "Cleric of Races". Allow me to explain. Chances are they're not the 'first-best' of traits that you could get out of any other race. But they're the second-best at a lot more than most could ever dare. Dwarves may be more tied to craft, Elves to magic, Humans to art, Orcs to combat, Tieflings to mischief, Halfings to Tradition... but few races understand all of those things combined more than a Gnome.

They're like genial grandparents that smile and give a "That's nice, Dear" to the rest of the world when they boast of their accomplishments.

...At least, that's my take.