Shi Blos was a relatively poor farming kingdom. It joined Tiresia almost immediately after Flauson, afraid of the war arriving at its doorstep. The region isn't particularly fertile or otherwise productive, and the area is considered a drag on the Empire by the rest of Tiresia, only tolerated for its use as a bulwark against the Frost Giants.
The key advantage that Shi Blos does have is a population who are used to trading and dealing with the few Frost Giants who venture that far west, and are the only people the Frost Giants trust to deal with.