Former Discount Tire employee here:
I wouldn't lean too heavily on those tread wear ratings. They are only really comparable within the lineup of a single manufacturer. Since every manufacturer tests them on their own, you can't really use that as a spec to compare tires from different brands. You can rely on it more as a ballpark for how long the tires will last, but a 300 from a MAST brand (Michelin, BFGoodrich, etc.) won't really mean much compared to a 300 from a Goodyear brand besides general tread lifespan (i.e. they might both last within 20k miles of each other....maybe).
Traction is much more dependent on the rubber compound itself and the design of the tread. The best thing to do is see what people are reporting for performance characteristics in regards to what you want out of the tire (dry grip, water evacuation, tread life, etc.) and scale that accordingly for a lightweight car like the Goblin.