Having double jointed/hypermobile hands + fingers

[pies]

Is this advantageous or disadvantageous for a pianist?

[invictious]

Well you can play with your hands upside down, otherwise it can be a disadvantage if it's like hard to control or whatever, but I don't know because I am not double jointed.

Depends on what kind of double jointed too, in some cases, you can stretch further with thumb and index finger, but I don't see much advantages or disadvantages.

[sevencircles]

Rachmaninov was doublejointed I believe and Albeniz too.

Rach. could do stretches that was impossible for almost everyone else.

He could reach a 14:th with his left hand during his prime.