Is positional play overrated?

Thanks

12.hxg hxg 13.Bh5 would have been a flashy finish too.

Sometimes extra pawn islands is a game ending weakness. Sometimes it doesn't matter at all. Sometimes it's compensated for by something.

In the OP position, what stands out to me is weak pawns vs a knight that has multiple outposts (knights are often good at harassing such weaknesses). Plus black's minor piece is a bad piece. As for which pawns, specifically the h and f pawns seem weak (d6 is well supported for now).

Pawn islands contribute to this, but they don't make the whole evaluation. White could have 4 pawn islands but if black's pieces are bad then black is the one losing. Or if we change the position so that white can't come into contact with black's weak pawns in a meaningful way, then black is totally fine. For example change the knight to a bishop (of either color) and it may be a simple draw (as I said, knights are pretty good for harassing weak pawns).

I could win that position.  Positional chess is absolutely not overrated.

Carlsen just made his case for positional play in crushing Harikrishna's IQP position. 

It's not a direct win with exact movements, but overall, as others have said, black is significantly stuck in his position and has to give up material in order to open up and can't exactly exploit any immediate weakness, while white can afford to improve their position by pressuring Bishop and d6 as well as potentially threaten c7 pawn through a6, meanwhile he can push black rooks out of f file and and advance with king and pawns supported by rook and threathning d6 even more.

I would win Silman's position in 5 seconds. Step one: Double rooks on the d-file and pin down black's pieces in defense. Step 2: Bring the king over to the queenside and start pushing there. Step 3: Advance on the kingside. 

Basically, improve the position of all your pieces to the utmost and break through. Game over.