Comment by jolmg

If you mean you prefer pinch/spread for zoom-out/in, I prefer the status quo with trackpad 2-finger scroll for zooming.

Pinching/spreading with index and middle finger feels unergonomic. Using my thumb on the trackpad would also feel unnatural, as would putting my 2 index fingers on the trackpad.

2 finger scroll is something you can "fling" such that the zooming motion continues even as your fingers have been lifted off the trackpad. Trying to "fling" a spread-out motion with your index and middle finger is an awkward motion, and of course in a pinching motion, your fingers would just crash into each other, so you'd have to lift before they crash. Pretty awkward.

On the phone, I often prefer tap then drag up/down (i.e. touch, lift, touch, slide) to zoom in/out with a single finger. It allows me to "fling" the zooming motion so it continues after I've lifted my finger. It makes a phone's interface behave like a trackpad's scrolling-zoom.