Prior to my current job at Aristocrat Autosport, I used to work for Weds Wheels North America which is the official distributor for WedsSport wheels in the US in Canada. This is exactly what the GM for WWNA said:
Hub rings are NOT required, however they are highly recommended for mounting ease of use and, and you should use them if you encounter vibration. He states that you can use wheels without them but he highly recommends that you should ESPECIALLY for hubcentric wheels, which is why for my 5x112 WedsSport SA-10Rs I always use hub rings.
The hub rings provided with the WedsSport SA-10Rs are made by Prestige Wheel from polycarbonate. Prestige wheel invented the hub ring originally for use in the limited run 1989 Shelby Dodge Dakotas as OE equipment, where Chrysler called for a wheel which had a locating system which would not be susceptible to galvanic corrosion. In the 1970s, the Pontiac Firebird's factory wheels had an incredibly tight tolerance on the hub and locating surface. The wheel and hub were made of dissimilar materials which caused galvanic corrosion, sticking the wheel to the hub. Within a few months of the car's release, Firebirds were being towed back to dealerships on flat beds as owners with flat tires could not get the wheels of the car.
In the case of the Shelby Dodge Dakota, the OE wheels were designed with an non-hub centric hub on purpose, as Prestige wheels' solution was to use a non-metallic reducer bushing of sorts to stop galvanic corrosion. This reducer bushing was essentially the first hub ring; its polycarbonate construction acted as an O-ring.