It's just math. If your trailer is withing the payload capacity of the SRW then a dually isn't necessary.
If you're talking about a better towing experience than the dually will almost always be more stable and handle better with just about any trailer.
I've been towing all manner of trailers and equipment behind my dually for 15 years. I just hook it up and go. No sway bars, no WDH, just a ball. It always tows great.