Cage Length (Rear Derallieur) and Total Capacity My drivetrain required total capacity is 14.

(folding bicycle Dahon Eco C6, 14-28 rear, 1x front)

The rear derailleur (Shimano TZ50, which I purchased), has total capacity = 34 and a long cage. Are there are any disadvantages, in such overkill, when total capacity of the derailleur (34) is much higher than required (14).
There's a huge disadvantage for a Dahon and any other small-wheeled derailer bike, which is that the cage is gong to be unfortunately close to the ground no matter what you do, and having a longer cage than necessary makes the problem worse.

Shorter cages also manage chain slap better and are lighter.