Linked from
The 14 pages that link to Supremum norm, each with the reason it gives.
Cauchy estimatesRelated: The estimate uses the function's supremum on the contour as its size input.
Weierstrass M-testRelated: The M-test bounds each term uniformly using this norm.
Siegel's lemmaRelated: Many formulations bound the largest coordinate of the integer solution.
Agmon's inequalityRelated: This is the pointwise-size quantity Agmon's inequality controls.