When I am saying it's unfair I mean that is why the whole topic of long putters is being looked at again by the R&A and the USGA to determine if it's an unfair advantage or not. Sorry if I didn't get my intended point across properly.
I know this is going to sound redundant, but I think pros and amateurs are always looking for ways to build our confidence. The long putters reduce extra movement. It's easier stay steady over putts and stops the trembling over short putts. I'm sure that Vijay and Phil were trying them out for that very reason as they both have an elite game except for their putting which is at best, mediocre.