To start with, the fact that the manufacturer includes the instruction set and address space size before the heat-up time makes me pretty skeptical. I get that its hackable, and that's cool and all, but as with all "smart things", I care about the "thing" part way more than the "smart" part. I can implement a PID controller in about 20 minutes (maybe an hour if I need to bit bang the pwm output) on any number of microcontrollers; that's the easy part.
Also, the USB-C power supply is going to be nothing but a headache. I already have drawers and drawers of usb cables that can't handle the current I want to use, now I need to keep careful track of my soldering cable, which only performs at 60W over USB (and at best 90W using a barrel jack supply)? And the iron doesn't even come with a power supply, so you have to go source that too. It may be $40 for the iron, but then its another $10-40 for the power supply, plus (as you say) an appropriate stand, brass sponge, etc, etc. Suddenly, the dedicated station like the (very affordable Hakko FX888D-23BY) starts to look pretty good.
The pinecil seems like a good thing to keep in your crash bag, but it feels a bit like refusing to buy a power drill because your swiss army knife has a screw driver.