Furthermore, as stated there is an actual button - which means zero latency
I have to take issue with this whole "zero latency" statement. On any game system, whether it be console or PC, there is no such thing as zero latency. Even if the console acknowledges your button press instantly, you still have the latency between now and the next framebuffer update to the video screen, which is at least 1/30th or 1/60th of a second.
On modern consoles, it is even worse. The PS3 uses a bluetooth communications protocol with it's controllers. This means that your button press has to be packetized and sent through the 7 layers of the OSI model across an inherently slow and subject to interference wireless connection, then depacketized and processed by software on the other end. The best thing you can hope for is that you only have 25-50 ms of latency and that it is unnoticeable to most players. This same thing is true of Xbox360 and Wii as well.
If you want to minimize latency, first you have to get rid of all wireless controllers and go back to corded joysticks or keyboard controls. Then you need to get a framebuffer (and CRT) that can refresh at 120hz or higher. This is why professional FPS players don't want anything other than a keyboard, mouse, and a real CRT. With a 120hz. refresh rate and a hard-wired keyboard/mouse, FPS players can get their latency down to around 8.33 ms (1000 ms in a second divided by 120 frames per second) which, while faster than most players can react, makes a difference to fighter pilots and other trained professionals.
All of this has been dumbed down in modern consoles to the point that latency is an extreme joke and we must calibrate our Rock Band setups to account for almost 100 ms of latency due to slow processing HDTVs, wireless controllers, and interference.
Give me back my keyboard/mouse, and Sony Trinitron CRT any day - and get off my lawn!