Apart from portability, the 12.9 is better than the 11 in every way.... how does the 11 "kick the ass" of the 12.9 exactly?
And it's not "insanely huge and heavy", I'll give you it's 50% heavier than the 11", but it's only just over an inch bigger in width and height.
Do people carry these things in their outstretched arms or something like that "hold the car batteries out at arms length" event in World's Strongest Man?
Let's get some numbers straight here instead of using vague terms. Speaking of exact dimensions, the 12.9 pro is 11.04 x 8.46, the 11 is 9.74 x 7.02
That means the 12.9 is 1.3 inches longer and 1.44 inches wider. To me that's more than "just over". Also, only speaking in terms of linear length is misleading because the real number we should be looking at is total
surface area. The 12.9 is 93.4 square inches in surface area, the 11 is 68.37, which means that the 12.9 is a hair over 25 square inches larger in terms of surface area, which is pretty dang significant! The 12.9 is a whopping 31% larger.
Here's some context for that - the difference between the size of the 11 and 12.9 inch iPad Pros percentage-wise is GREATER than the difference between the iPhone SE and the iPhone 12 Pro MAX! The 12.9 iPad Pro is 31% larger than the 11, the iPhone 12 Pro MAX is 30% larger than the SE.
This difference can mean quite a bit. For example, I had both iPads for awhile and in my ultra-light backpack the 11-inch slips in perfectly whereas the 12.9 doesn't even fit because the zipper won't go around the corner. In my regular backpack the 11-inch fits in the front secondary pocket just fine, the 12.9 doesn't fit at all and has to go into the main pocket, it fits awkwardly in there so it eats up more room than it should. I'm sure this is also a problem with some women and fitting their iPads in their purses.
The added length on the 12.9 further exacerbates the weight because that additional length acts like a longer lever, adding additional pressure on your hand when one-handing the device.
I had both iPads in a previous gen so I have no horse in this race, the 12.9 works better in some situations for sure, but for me I grabbed the smaller iPad 99% of the time because I found it far more enjoyable to use, especially when out and about or lying around. I basically only preferred the 12.9 when on a desk.