Basketball shorts are obviously made for the game. They are designed for free movement and overall comfort when ballin’. Designing them with a longer inseam guarantees a full range of motion, which helps with irritation or them bunching.
Athletic or gym shorts tend to have a bulkier appearance at the top and sometimes come with pockets. You won't need pockets with your basketball shorts because it'll weigh down the intention of the light material and more than likely you’ll have items flying out while you are playing.