Often you hear people talk about how 3D touch isn't discoverable or even very useful. Likewise
you make hear people talk about how useless the Touch Bar is as well. I don't believe that needs
to be the case for either feature.
What I do think these features lack is universal support. What I mean by that is when these
features are created they'll show up on some devices but not others. So, you get some phones
that can do 3D touch and some that can't. Even now years after it's introduction. Touch Bar
is only available on some Macbooks but not others and it's unavailable on any desktop Mac.
So you're left wondering why should I invest time in learning this new thing I can't use
on all my devices and developers are left wondering why should they support this feature
which won't benefit many users and may only end up a novelty that goes away.
The Touch Bar removes a whole set of keys and changes how you interact with your
apps. If it ends up being a "sometimes" thing then that's just not good enough and a
waste of Apple's engineering resources.
This will also affect their efforts to promote Apple Pay too. It's a great feature and
I'd like more websites to support it but using Apple Pay on your Mac with your iPhone
is at best a tricky operation so providing the option only provides a good experience
for a minority of Mac users.
3D touch is a little more tricky as it is a complicated engineering feat by Apple's
own admission (See the Phil Schiller quote on the verge's article on 3D touch). This means it will likely never show up on the iPad because of
that and perhaps shouldn't given it would probably become quite unuseful when the
iPad hooked up to a keyboard. So yes, it is in an odd position where iOS support won't be
universal but they've spent the effort and quite a bit so at least make it universal on
the iPhone. Otherwise, what's the point?
I still believe 3D touch is quite useful on the iPhone but again, three new devices were
released in 2018 and one of them did not have 3D touch. If it were universal then people
would share tips and tricks that help spread the knowledge that it's there and how
useful it is. But now, why even mention it? It can likely be an option that isn't
even present to the person you're sharing the information with.
It would be a shame to hold back new innovations but if they can't commit to it and
spread it to as many users as possible then maybe they should consider holding off until
they can do just that.