I think 3d touch has problems but they are all tied to software. I find it extremely useful for keyboard cursor. It requires some finesse but the 3d touch version (as opposed to the long press available on iPad and iPhone XR) is more useful as it can do selection by changing pressure. It is not very accessible as it requires some finesse though.

Another feature I use all the time is 3d touch on apps which have quick shortcuts.

Where I agree is that there is too much of a fine line drawn between long press, drag and 3d touch and it is far from easy to be able to activate the desired one 100% of the time.