Yes, you need the pot to set the THC target voltage, which, of course, translates to cutting height. The value doesn’t change by much, in my experience, but it is different for each type of material you cut (material and thickness). As you can see in my set up (Finally completed my CrossFire mods), I have it mounted on my front panel. @Dicky has his mounted on the side of the Control box so it is relatively accessible. If you cut a lot of the same material in a row, you could easily forget to adjust it when moving to the next material.
You might get away with mounting it separate from the THT03 electronics, it’s a 10K ten turn pot and the THT electronics has pretty good filter, but I can’t attest to it’s noise sensitivity to a remotely located pot.