Yes it is low mileage, but not zero, so it can still be used sensibly.
Putting on 500 to 1000 miles a year, fun driving to local events, out and about in the summer months, is hardly going to destroy its low mileage status.
Such motoring is enough to keeps it in good fettle mechanically too.
My 4200 only had 11.5K 5 years ago, and 16.5K now, and I have used it as much as I can with other cars to use too.
I the case of this car inparticular, you might well be right.
5k miles is obviously low, but it's not zero. Looks like it's priced as a zero miles car though. I'd say pushing the miles higher will knock the value down substantially (assuming there is someone out there that wants to buy it at it's current price)
Your 4200 at 16.5k will demand a premium above others (especially my near 70k example!) but a 5k 4200 would demand a premium over yours, and a <1,000 miles car even more.
Personally, mileage and use wise, I'd put yours above all the others. Used, taken care of, but equally cherished, but then I'd use it too, so it then becomes a trade off between spending more on less miles, or saving a bit and getting an equally cared for higher mileage car.
I think this one is another for picking up to dust underneath every so often, to sit in the garage equivalent of a mantle piece. An ornament, to look pretty. And if you have the cash, it is a pretty ornament, so why not?