Why is an isolated queen pawn so special? Various articles and books mention the following advantages of having an isolani:


Better development 
Outposts on e5 and c5 
Constrained Black position


What I don't understand is how are the above mentioned advantages specific to isolani? Any side which gains centre control will get these advantages, right?

So back to the question, what makes isolani special? If I have an isolated pawn at some other file say c-file or e-file, the same rules will apply right? I'll still get the same advantages while having the disadvantage of being isolated.
It is mainly so special because it can arise from many different openings, both open and closed, e.g. the Queen's Gambit, Nimzo-Indian, Caro-Kann and the Alapin variation of the Sicilian. It is simply much more common than a mirrored situation with an isolated pawn on e4, which would require exchanging the white f-pawn, which often stays on f2 to protect the king. In general, an early isolated pawn on the n-file requires an early n4 move by White and n5 by Black, followed by undermining pawn moves in the adjacent files. Those are most likely to happen on c-, d- and e- files.

An IKP (Isolated King's Pawn – an isolani is often called an IQP) would give the same advantages, but in addition:


it would be harder to defend than an IQP
assuming kingside castling, the half-open f-line would give White even more attacking chances, at the cost of being more exposed as well


A isolated c-pawn is even rarer, and has less influence on the center than a d- or e-pawn. All other things being equal, this is definitely a disadvantage for the side having an isolated pawn.

Hanging pawns are another commonly occurring structure where (potentially) weak pawns have compensation in the form of center control and space advantage.