Two completely different objectives could be accomplished. Helicopters will be better for sightseeing on short distance flights (usually less than 20NM radius). Helicopters have a much higher cost per hour and per passenger. Hydroplanes will be better to transport tourists to remote locations with higher useful load (more people and with baggage), through longer distances and lower cost per mille and per passenger. In this scenario they are great. Hydroplanes could also be used for sightseeing (but even high wing hydroplanes provide worse tourist experience - if the goal is sightseeing - due to worse visualisation and higher speed when compared to helicopters).