It seems there’s a disconnect regarding whether the ‘persistent’ preference should apply to parameter values as the documentation and the designer explainer pop-up suggest or parameter instances themselves, as @osolorzano suggests in this thread.
Clearly as of now, it seems the latter is the case, but i’m strongly in favor of the former, and what i imagine was the original intent - no sense having properties just disappear, especially if they don’t really disappear in the JSON (which would break things anyway), but just become invisible in the designer.
And like @tyrel.parker suggests - these parameters are often modified for testing, and so should not retain their ‘test’ initial values just because someone forgets to clear the test values, regardless if they will likely be immediately overwritten by bindings at run time. I’ve had an embarrassing situation where comms were lost, and on view reloads across the plant, the obviously very-wrong ‘test’ initial values were displayed. Thus my desire to make all my bound property/view parameter values non-persistent.