There’s an added benefit - shorter flange distance/ larger mount diameter. Nikon especially went with a large mount. A larger mount = potential for faster glass.

But also think about it from a marketing perspective - even now most people buying cameras aren’t professionals. A big bulky camera right next to a svelte one in a store will look dated. That said Sony went too far with it, in my opinion. A nice grip is important for professionals.

I've been trying to keep up with all the new photography concepts in this thread, but "Faster Glass" is throwing me off?

How can glass lenses be "faster?" Allow you to shoot with a faster shutterspeed?

Faster is taken to mean that a lens has a larger maximum aperture, meaning more light gets in, so you can use a faster shutter speed, and hence get less motion blurring. Non-intuitively, because depth of field gets smaller as the aperture increases, faster lenses can also offer better separation of the subject from foreground / background features

I think that's correct (because it lets more light reach the sensor due to the bigger aperture, so less exposure is necessary)