Are expensive organizers like Peak Design or Bellroy worth it over budget BAGSMART or FYY cases?

It depends on use. Verified-purchase ratings show budget cases (FYY, BAGSMART) satisfy the vast majority of buyers for occasional travel at a fraction of the price. Premium options from Peak Design and Bellroy command their price through build quality, materials and organization design, but the rating data alone doesn't prove they're functionally necessary for most users.