This is particularly important for indie games, which often have few daily players. Gamers are more likely to keep playing a game that seems to be played by many people.
I ask because personally, the daily ranking allows me to evaluate myself on an "objective" basis versus other players on a given day (i.e. if I'm 50th out of 100, I'm roughly average).
Hot rankings don't exactly give me this, because how/where I rank will depend not only on my skill, but also how long ago I made the score, the timing of other high scores, etc.
The main benefits seems to be a larger leaderboards and a higher ranking when you get a particular score. Personally, I don't see those as huge benefits.