Bal has more than just the beautiful beaches that other locations offer. There is the Balinese culture (temples and massages etc), mountains to climb, natural wildlife to explore, and a vibrant tourist scene in general in a compact area.
Things you won’t get in Fiji or Mauritius (the hotels with lovely beaches are secluded from the local population areas). It’s jusy my observation.
This forum is focused on Hilton hotels and associated information, but it seems you are still researching on a vacation location, not hotels.You could start googling a bit, and also search the Hilton website for info on the various properties in each location. That will help you have a clearer picture and this ask more specific questions.