I've never really understood why one would want to have double kettlebells of the same size. I'm a bit poor (or cheap) and heavy kettlebells are expensive in my country. I just have one of each from 16kg to 48kg in 8kg steps (16,24, 32, 40, 48...)
I don't see why one just can't take a 24kg and a 32kg, do some front squats, rest, switch and do some more.
Not having a balanced load is more "reality based strength" in my mind, like when you carry a sofa or a fridge. They're not going to be balanced evenly.
And when you press a single kettlebell the other side of your body has to work hard to have you standing upright.
And better to swing one heavy bell than two smaller ones, there's only so much space between your legs before you risk hitting something.