The only time last.fm is completely useless for someone is if you just fake all your scrobbles. Like the entire point of it is to know how much you've listened to an artist/song/album, and your most listened to in a timeframe. If you're gonna sit here and make a fake amount for every song then what is the actual point? To stare at fake data?
The people with like 1,000 scrobbles for every song by their favorite artist. A mess. We're suppose to believe you listened to Hilary Duff's flat voice 40,000 times?