What immediately struck me about the ABDO was that it would be a relatively inexpensive way for a woman who wishes to purse carry to transform any purse large enough to accomodate the ABDO into a CCW purse. Although you would no doubt sacrifice a second or two of time vice how long it would take to draw a pistol from the ABDO when it was mounted on the belt, many women prefer not to carry concealed on-body for a variety of reasons. For those of us who choose to carry off-body in a purse, we may find that once we've splashed out for a handgun, a case, cleaning accessories, safety accessories and a training class or two that our wallets are in desperate need of relief. Dedicated CCW purses, especially the ones of the highest quality, can be quite expensive. For many women, simply securing the ABDO inside her current purse may be a way to save some money while still keeping the firearm secure until it's needed.
Another way in which traditional holsters can fall short is travel and storage. Although the ABDO shouldn't be thought of the same way you would think of a full-sized gun safe, it's constructed of tough polymer and it locks, so it can certainly serve as a discreet way to secure your gun, especially while you're traveling. Say you're driving to a business meeting, when suddenly you realize that you cannot bring your CCW into the business venue for any number of reasons. Rather than having to go through a conspicuous unholstering routine followed by conspicuously locking it in your trunk, you would simply remove the ABDO from your purse and lock it away in a glovebox or center console. The casual observer would have no way of knowing that the case contains a firearm, and you wouldn't have to actually handle the gun itself in order to secure it.
Additionally, the ABDO would represent a great way to secure items other than your firearm. For example, if you're one of the many people who must keep prescription medication with them that is attractive to drug abusers—painkillers, for example—the ABDO would serve quite well as a way to lock your medications away from unauthorized persons. While you were at it, you could go ahead and use it to secure your passport or other important documents...even an actual cell phone.
Shooting Illustrated has a comprehensive review of the ABDO, including a list of firearms that fit it, here. Don't miss it!