There's practically nothing that a shotshell-firing revolver can do that a regular bullet-firing handgun can't do better. (With the possible exception of firing small loads of very small shot for executing snakes at close range without fear of ricochets.)
They certainly aren't easier to hit with. You still have to aim them just like any other hand gun, except now your projectiles aren't all going to go just where you intended. They are large and unwieldy. Many shooters don't take the time to become good DA revolver shooters, and so DA revolvers get a reputation as being harder to shoot well than common auto pistols. Making them larger and heavier to hold shotshells doesn't improve that.
Further, few knowledgeable shooters or instructors recommend anyone plan to defend themselves with shot loads of birdshot, but .410 bore shells don't hold much in the larger shot sizes. The shot, or "disc" or whatever payloads aren't as terminally effective -- by FAR -- as normal bullets.
Of course, they can work. Anything CAN work. But in a defensive situation where lives are at stake in split-second moments of action, the wise person would chose whatever stacks the odds most heavily in his or her favor. What's most likely to work best.
Back in the days of the old Thunder 5, and then again when the Judge series came out and were so heavily marketed, and again when S&W jumped on Taurus' coat tails with the Governor, there were small flurries of articles about using them for defensive purposes, including imagining scenarios where they might make some sense as a purposeful choice for self-defense. The farther we get away from their big product launch debuts and the burst of enthusiasm surrounding that, the fewer articles we see where people try to make a serious case for choosing one for self-defense.