Sure, it takes up some space. But so does having to carry dongles. If Apple made an iPhone with the jack back again and a couple percent smaller battery, I'd take the jack. The phones has already been getting thicker every year ever since 6 (the 2nd last iPhone so far with a jack), so that's no argument.

Right? Not to mention the dongles break super easily and also I can't charge my phone and listen to music at the same time :/

I imagine it helped deliver on another feature customers have been asking for for years, which is water proofing.