I'm sure but why would you want Apple Pencil support on an iPhone? Very few people would be using the Apple Pencil with their iPhone. It makes sense on an iPad, not iPhone.
That and dual-SIM were two features that would've made me upgrade from my X, since the 13" iPad isn't particularly easy to carry around in case I get an idea I want to sketch. In fact, it's easier to just bring pen/cil and paper, and while Procreate Pocket is improving, it's nowhere near something I'd call more usable than pen/cil and paper. So, for me, it would be a big win to be able to ditch pen/cil and paper in favour of the Pencil, as well as not having to carry a second phone around at all times. Hell, if the Note were smaller, I'd probably have switched to that instead of the X at the time I made that switch.
Lots of features are used by relatively few customers, or used infrequently. That doesn't mean they don't have value, or that the customer loyalty it breeds when you encounter a device with just that set of features you need isn't valuable. People use the features that make sense for them, period. I don't see any other issue than weighing cost vs utility, and this doesn't seem like something that is likely to have a significant cost to it.
For me, the new phones (if Kuo is accurate) offer nothing over the X, and may be a step back. If the Force Touch bit is pulled, a significant step back, along with another hit to confidence in the platform, since removing features while they're still being used, without introducing a meaningful replacement, is the sort of thing I primarily associate with (pseudo-)monopolists losing the sense of sensibility one should have as a (pseudo-)monopolist.
YMMV. For many, yet another minor spec bump in the refresh game may be just the thing they want.