My memory is bad also. Here is what I think is true. Softbody interacting with primitives was fine. Softbody interacting with basic props was fine. Softbody interacting with another softbody was fine. However, Softbody interacting with a rigged object had calculation issues. When a softbody physics object interacted with a rigged posed or rigged animated figure, the calculation times were too taxing for someone like me and my computer at the time. I have since gotten a new computer and do wonder if softbody physics is wiorth revisiting, but the VWD plugin does most of what I would want.
Back in the day, folks like Marcus Severus were able to greatly reduce render times by creating a softbody envelope attached to the body parts of a rigged object. They then turned off collisions for the rigged object. The result was that the softbody cloth would interact with the softbody envelope, and those calculations usually went more quickly. The problem was getting the envelope to match the movements and pose of the rigged figure. The last I remember was an experiment with target helpers.