Dufferin Islands is a worthwhile secondary stop in Niagara Falls, especially for travellers who have already covered the obvious headline sights. It gives the local itinerary another angle and can make a route feel less generic.
Use it as part of a cluster rather than a standalone detour unless the subject is a personal interest. Confirm current hours and access, then give yourself enough time to look around without turning the stop into a box-ticking exercise.