I know PART of the reason they put on allen or torx head screws, it is to reduce damage to the screws from ham fisted idiots using anything that fits in the slot instead of the proper tool.
I said "reduce" instead of "eliminate" because of things like this...
Regular old screwdrivers often fit those new fangled screws, as long as the flat is the same width of the hex or star version.
The most common damage to firearms is damaged screw slots. The most common cause of that damage is from people using "regular old screwdrivers" in those screw slots. Or anything else that "fits" including knives, chisels, spoons, or anything else handy that "fits".
because they don't fit, PROPERLY. It is the "slop" in the blade fit with the screw slot that allows the screwdriver blade to "slip", and damage the screw slot. Hollow ground screwdrivers are today, common and cheap, and can be found in sporting goods stores, unlike decades ago, when they usually had to be ordered.
using an Allen head, or something else means you need the right tool and almost nothing else will work. USING something else sometimes works, but can also damage the screw. Ever seen an Allen head screw with the hex slot all "rounded out"? That comes from using the wrong tool. (or the wrong size). When that happens, the damaged screw is very difficult to remove, and may require drilling it out.
The upside is fewer damaged screws, because people looking at the hex socket are not going to just grab a screwdriver out of the kitchen drawer and use it on their guns. Of course, some people are going to try that, anyway, there's nothing we can do about those people.
The down side is that one needs a special tool like an allen wrench or torx driver, which may not be available unless YOU have planned properly and have the right tools available, and are patient enough to get them, and use them (some people aren't).
I much prefer slotted screws, and I do have "gunsmith" screwdrivers. I prefer slotted screws because, in an emergency, you CAN use other things on them. The trick is only using the wrong screwdriver (or butter knife) when it IS an emergency, not when getting the right screwdrivers is just an inconvenience.
The original GI 1911 & 1911A1 could be detail stripped, including all screws, using only one "tool" (anything small enough to depress the firing pin), all the other needed "tools" are the parts of the gun itself. This is a big plus for a combat weapon, where the solider might not have the right tools with him in the field.
While it mildly irritating needing a special tool for the grip screws, what bugs me more is the "proprietary" SPACING of the grip screws. If you get a S&W 1911, standard COLT (or USGI) grips will not fit! You have to use a S&W grip, or one made for that specific make & model gun. My son has one of the S&W 1911s, so I know this from personal experience. I don't know if Ruger, or Sig, does it as well, but I suspect they do...