Any heat treated alloy will have minimal benefit from hydroforming since this process does not substantially alter the grain structure of the metal. The yield strength of the material is based on the heat treatment.
Hydroforming is useful for complex shapes but the bicycle from does not need this extensive shaping. But I might have some bias since I think contoured tubing is silly. Butted tubing is a sound engineering design but making a round tube into a cloverleaf profile (or any other shape) is just a marketing gimmick. And putting intentional dents in tubing for "compliance" is downright dangerous on aluminum.