Ironically Square isn’t good at anything in particular. Square fails to have a good point of sale (Toast wins) and fails for online store fronts (Shopify wins). Square is in a position where they spread themselves thin and aren’t at the top of anything in particular.
With light CRM, Staffing, and Banking tools, it seems like Square's strategy is to be best-of-suite for small businesses rather than best-of-breed.
I've never seen Toast outside of bars/restaurants (although they are ubiquitous in that segment). Every other service or retail shop has been Square, especially farmers markets and craft fairs.