That's more realistic, but it won't guarantee that you won't get in trouble with the law. Every situation is different, just understand ahead of time that whenever you get involved in a deadly force situation, you will most likely need to justify your actions down the line. If you are able to articulate to the police or a judge your reasoning for your actions, it will benefit you.
I've seen forums where some folks advise to not talk to the police until you get a lawyer if involved in a deadly force situation. It's their choice, I hope they understand that will probably lead to arrest and booking for the most grievous crime apparent at the scene. Then, you can call a lawyer from jail - or a family member who will contact one for you - but that still leaves you with an arrest record for...? ADW... Attempted Murder... Murder?
Understand as best as possible what criminals do, understand how the responses you carry in your "toolbox" are percieved by the legal system in your area and plan and train accordingly.
Any device, whether firearm or slungshot, doesn't guarantee a successful outcome of an incident or freedom from prosecution.
I just don't see how someone can promote a device like this without also presenting it's shortcomings, limitations and legal implications. You may be talking to folks here with little knowledge of what occurs on the street and in the courtroom and giving them false hope.
The right to self-defense comes with responsibilities.
This is just my .02, I'm no expert. This device may be new to a lot of folks and I'm just trying to provide some things for them to process for a more informed decision.