Birds like the hummingbird visit flowers to drink the nectar, wasps and hornets for the same reason,so do a lot of flies and beetles. Bees do it to collect pollen which is taken back to the nest to be turned into honey. All the creatures that do this help pollinate the plants and are of great benifit to us in the production of our food.Another thing wasps and hornets do that helps us greatly is catch flies and caterpillars, which they take back to the nest to feed their young. The adults live on the necrar and pollinate at the same time. It's better for us when we let them live.