The limits being talked about here are altitude limits
D'oh! Well that makes sense.
Regarding "park" I guess the negative I can think of is what I've experienced with mine, that being:
since "Park" is a prominent option, i.e. a button for it exists in more than one location... if you can't set up some mounts to park, then the existence of the button is worse than useless because accidentally pressing it sends the mount moving to some position (which seems random on my mount).
In my case, that "random" position has, 50% of the time, been such that it will crash the mount unless I intervene to stop it. Obviously, if a guy wanted to set up his rig to remotely control it, then an accidental sending of a "park" command is a significant problem.
If some mounts can't "park", then maybe having an option to select whether or not you want the buttons to be present at all on the controller screens or not would be a good thing? In the case of these types of mounts, at best it's a dead button, at worst accidental pressing of a button you can never use but is always present can possibly damage a mount.
In other words, in my case (and others), since my mount apparently can't park at all, if I could make the button disappear altogether on the control screens (or be grayed out and non-functional or whatever), then that could very well protect a guy's equipment from being damaged. Seems like a pretty good idea.