When you hit a key, the keyboard has to decide the exact moment that counts as "pressed". That sounds trivial, but it is the main thing that separates a cheap keyboard from a gaming one, and it explains most of the jargon on a product page.
There are three common designs. A membrane keyboard (often called rubber dome) has a soft dome under each key that collapses and connects two layers. A mechanical keyboard gives every key its own spring and switch, and the press counts when two metal contacts touch. A Hall effect keyboard hides a tiny magnet in each key and uses a sensor to measure how deep the key is, so the keyboard itself, not a metal contact, decides when a press counts.
The actuation point is the depth where a press registers. Many standard mechanical switches actuate at around 2 mm of roughly 4 mm total travel, though it varies by switch. Low-profile designs are shallower: Logitech lists 1.3 mm for its G915 X. A shallower point means a press counts sooner, but it also makes accidental presses easier when your fingers rest on the keys.
On a regular mechanical switch the point is fixed when it is built. On a Hall effect keyboard it is a setting. The MCHOSE Ace 60 Pro, for example, lists an adjustable range of 0.1 to 3.4 mm.
Drag the key down and let go, or play the example taps. The top lane shows a standard mechanical switch with a fixed point. The bottom lane shows a Hall effect key you can tune.
On a normal switch, a key has to rise above its reset point before it can count again. Rapid trigger removes that wait. The keyboard watches the direction you are moving: let the key rise by a small amount (the sensitivity) and it releases at once, push down by that amount and it fires again, wherever the key happens to be along its travel.
Play the example taps with rapid trigger on and then off. In the first burst the key never rises above the mechanical reset point, so the mechanical lane counts a single press while the Hall effect key counts every tap. In the second burst the key lifts almost all the way, so both count every press. That quick stop-and-go is why shooter players like it: you stop moving the instant you let go of a movement key, then start again just as fast.
It is not magic. A fast press-release pattern needs a keyboard with the sensor and software to read depth, and it takes some getting used to. Beginners will gain far more from learning the game than from the switch.
Not to start. A decent membrane keyboard is fine for learning games, and a regular mechanical keyboard is a good step up if you want a crisper feel and the ability to swap keycaps. A Hall effect keyboard is worth a look when you play fast competitive shooters or rhythm games, where tuning each key's point and releasing instantly can matter.
Decide between a conventional mechanical keyboard and an entry-level Hall effect one. If you want the adjustable features, check that the actuation point and rapid trigger can be changed in software, not just advertised. Expect a compact layout at this price.
Choose the layout first: a 60% board has no arrow keys or number pad, a TKL (80%) drops only the number pad, and a full-size board keeps everything. Then check the connection (wired is simplest) and whether the switches are hot-swappable so you can change them later.
Here you pay for build quality, wireless that keeps up with wired, and long battery life. A very high polling rate such as 8000 Hz is a nice extra, but 1000 Hz is already common and the gain is small outside competitive play. Wired mode is the safe pick for the lowest delay.