As another 888 owner, I'm not moved.
As plenty of folks have said, the FX-888D is an "older" design in the sense that the heating element and tip are separate components. But, that isn't to say that this layout is obsolete - it's still very common and Hakko (among others) still makes new irons using the same system.
Given that iFixit's design uses a TRS jack as a tip mount, you can safely assume there will never be a hook tip for this particular iron, and wide chisels are probably out of the question too. That makes this iron a non-starter for me, but it all depends on your use case.
What doesn't depend on your use case is the use of a USB port as a power source. Sure, it makes sense for consumer products where compatibility trumps all. But, its fragile contacts and lack of shear strength mean that this isn't just a soldering station that's easy to fix, it's a station that you're going to need to fix.
The way I see it, FixHub is a gadget, and an 888 is an appliance. FixHub has several design decisions that compromise its sole purpose: soldering stuff. Direct heating elements are great, don't get me wrong. But if you're soldering frequently enough that a direct heating element would meaningfully boost your productivity, then a high-end RF induction iron would serve you much better. I wouldn't accept such a compromised tip mount and cable at any price point, let alone ~$350.