We've only used hoppers once and it was because we had a three day trip but wanted to hit all of the parks. I don't find them necessary for the way we plan our trips, but I could see them being nice for certain times of the year/certain reasons. For example, during Food & Wine it would be nice to hop over to Epcot at night or when the Halloween and Christmas parties are happening MK is pretty busy on non-party days, but not as busy on days with a party, so you may want to do MK during the day on a party day and hop elsewhere at night, but then on a non-party day do a difference park, but hop over to MK for the fireworks (since you can't see them on non-party nights without a party ticket)...so for things like that I think it's helpful otherwise, it's just an unnecessary added expense for us.
I also agree with others - for a first trip, there will be so much you want to do and see in each park, that you really won't have any reason to hop. Most people are hopping cause they know what their favorites are and they want to do them multiple times in a trip.