Nothing, including force on force, can take you all the way to "prepared" for a lethal force encounter. How and why you react can be partially conditioned. The more you shoot firearms and deal with stress inoculation whether in training or competition, the better your chances that those parts of the problem will not compound with the tragedy you will experience if you must be in a lethal force encounter.
That said, if there is a timer and a scoreboard, it is a game. No game can reasonably claim superiority over any other type of game when it comes to transference of usable skills in a lethal force encounter. To do so, to me is irresponsible and $ driven at best. Any dynamic, or action shooting game, will give some benefit, ICORE, USPSA, IDPA, USCA, 3Gun, 2Gun, even homegrown tactical matches. So too will courses whether from LE/Mil/Civilian and in a variety of formats.
Multiple forms of weapons handling skills, tactical planning, verbal judo, conflict avoidance, weapon retention skills, hand to hand skills, and yes, even physical fitness are all important aspects of personal protection/self defense. Over emphasize one or ignore the others. you may not be properly prepared. The larger the buffet you sample from, and work on requisite skills, the more "luck" you have stocked in your corner if you are one of the unfortunate ones to be attacked.