In order to make sure a string exists, I’ve had to use the “Matches” operator on the Compare Strings operator, and match it to a regex like [A-Za-z]
I would agree, this is probably the effect that @SteveCharles is looking for.
In the screenshot in the OP, I think the jsonpath evaluation is coming out to [1] (an array), which is different that 1 (a number). A compare on this same expression could be Matches [1-9], which would effectively be the same as > 0, if I’m not mistaken.
Matt