Typical of many insects (and even more so for butterflies), adult bollworms won’t cause any damage in the garden or vegetable patch. However, caterpillars and larva that emerge from their eggs can devastate nearby plants.
Hedges are important for biodiversity. Birds, for instance, love building their nests in them. It makes sense to regulate when to work on hedges and when to keep them undisturbed. Regulations on trimming and removing hedges is what helps coordinate this effort as a community.