It was in part based on a falsehood. The "tround" idea was heavily promoted and one major claim was that it took up less magazine space for a given caliber because the corners of the "tround" fit into the "empty spaces" in a magazine left by cylindrical cartridges. A few minutes consideration showed that to be untrue since the magazine space for a given number of rounds was the same whether the gaps were filled or not. In fact Dardick "trounds" had thick cases and so fewer could fit into a given space than conventional cartridges.
While the Dardick seemed to combine the best of the revolver and a large capacity autopistol, in fact it had few advantages over the former and none over the latter. The magazine was built in, and had to be loaded with individual rounds, a lot like the Johnson M1941 rifle. Dardick planned for a stripper clip, but I never saw one. In some respects, rather than having the best of both worlds, it had the worst. The complexity and timing problems of a revolver, and greater bulk and weight than the pistols of the day.
It also suffered from the "chicken and egg" problem in the gun industry. Until there was an assured ammo supply, no one would buy the gun, but no ammo maker would tool up to make the ammo until enough guns were sold to assure a market. Some "trounds" would accept conventional cartridges, like .38 Special, but that meant even greater bulk and reduced magazine capacity.
The gun and its inventor were widely praised for being innovative, and that is true. But being innovative is not enough, the product must also offer some significant and real improvement over what is on the market. The Dardick did not do that.
Jim