Based both on macOS documentation and on the experiences of people who use macOS:
> without Drag Lock: Double-tap an item, then drag it without lifting your finger after the second tap; dragging stops immediately when you lift your finger.
> with Drag Lock: Double-tap an item, then drag it without lifting your finger after the second tap; dragging continues when you lift your finger, and stops only when you tap the trackpad once.
> three finger drag: Drag an item with three fingers; dragging stops immediately when you lift your fingers.
It may well be that with current mac systems that have "force touch", it might be possible (or necessary) to replace some of those steps with "press hard". I stand by my statement that this is a lot of engineering and a lot of user adaptation in order to not have mouse buttons.
> To drag and drop something on the Mac, you: click it, drag it, and release it.
It's not true. On windows/linux:
tap, release, tap, drag, release
On MacOs:
tap, release, tap, drag, release, wait
When moving back and forth between windows/linux and MacOs, and after working for 20 years with windows, that "wait" isn't built in into finger-memory. So if you "move on" with the next actions, it means that you'll drag whatever you were dragging to the next button.
Are you... under the impression that Macs don't have, clicking?