The Scout Rifle is "a class of general-purpose rifles defined and promoted by Jeff Cooper in the early 1980s".  The concept is for a bolt-action, .30-caliber, carbine-length rifle, that can hit man-sized targets out to 450 meters with iron sights.  Such a rifle has obvious advantages, or at least little or no disadvantage in many traditional roles, such as hunting.  In combat roles beyond Close Quarters Combat (CQC)

The Scout Rifle is "a class of general-purpose rifles defined and promoted by Jeff Cooper in the early 1980s".  The concept is for a bolt-action, .30-caliber, carbine-length rifle, that can hit man-sized targets out to 450 meters with iron sights.  Such a rifle has obvious advantages, or at least little or no disadvantage in many traditional roles, such as hunting.  In combat roles beyond Close Quarters Combat (CQC) distances, it's effectiveness compared to modern semi-auto battle rifles is less clear.

A key performance indicator of combat is that you have to actually hit the enemy with accurate fire, or if you have a bad vantage point on him, you must get as accurate of fire on him as possible to "make him more concerned about not getting shot than he is with shooting at you or moving" so that you can maneuver. Movies and TV have given really whacked-out perceptions of how this happens. Soldiers fire their rifles on semi-auto almost exclusively, even though they have selective fire capabilities. To a soldier, "rapid fire" is probably about 30 rounds per minute, and normal firing rate is probably around 15/min. If this sounds unexpectedly low, think about the fact that a rifleman is likely only carrying 210-390 rounds, and you can see that firing 1-2 rounds a second, extremely rapidly, would deplete your ammunition too quickly and you'd have nothing left to finish the fight.

A Scout Rifle could maintain that firing rate, and a few well-disciplined soldiers, armed only with slow-firing, slow-loading bolt guns could lay waste to a bunch of untrained adversaries that blast away all their ammo ineffectively in a short time, and are exploited as they retreat, empty. So where would the bolt-gun be at a disadvantage? Everywhere else. In the initial stages of the confrontation, it is necessary to gain fire superiority, and this is usually trained to Special Operations Forces (SOF) soldiers as "expend your entire first magazine, firing accurately at seen enemy, or deliberately at likely enemy positions". In some tricky spots, such as while teammates move a casualty or mount into a vehicle, it may be imperative for only one or a few shooters to fire more rapidly or for longer periods without reloading. The Scout-type rifle also has disadvantages in the form a long barrel and fixed stock, making it more cumbersome inside structures or vehicles.  In CQC, small capacity, cycle time between shots, and time to reload would be deficits, at the very least causing a change in your tactics to avoid such situations.

The Scout Rifle could hold its own during the meaty portions of the fight.  There is certainly empirical evidence of soldiers armed with bolt-action rifles succeeding against enemy forces armed with semi-automatic rifles, throughout the 20th century.  I think the corollary question to ask would be "What are the disadvantages of the semi-auto?" and why would you NOT want one of those?  More complicated mechanisms increase points of failure and decrease reliability.  The capability to shoot rapidly lends itself to a loss of shooting discipline, just "spraying and praying".  Semi-auto rifles are often significantly more expensive, costing 1.5-6x as much, and low cost semi-auto rifles may be notably less accurate than a bolt-action.

These are just a few things to consider, if you're selecting a rifle for defensive purposes and weighing the merits of the Scout design.