Every keyboard turns a press into a signal. The difference between a mechanical and a hall-effect (magnetic) switch is how it decides you pressed — and that changes more than you might think.
How a mechanical switch registers
Inside a mechanical switch, a metal contact closes at a fixed point in the key's travel: the actuation point. To register the next press, the key has to rise back past a reset point first. Both points are set by the switch's design — you choose them when you choose the switch.
How a magnetic switch registers
A hall-effect switch has a magnet in the stem and a sensor on the board that measures how far down the key is. Because the board knows the key's position the whole way down, the actuation point isn't fixed — it's a setting. Want a hair trigger for movement keys and a deeper press for abilities you never want to fire by accident? Set them separately.
What rapid trigger changes
Rapid trigger uses that position data differently. Instead of waiting for the key to pass a fixed reset point, the key resets as soon as it starts to rise (by a small, adjustable distance) and actuates again as soon as it starts back down. In practice, letting go of a movement key stops your character sooner, and quick re-presses don't need a full lift. It's most noticeable in games built on precise movement — counter-strafing in tactical shooters, rhythm games, fast footwork.
When mechanical still makes sense
If you type as much as you play, love a tactile bump or a click, or simply like the feel of a particular switch, mechanical is still a great choice. Hot-swap boards make it easy to experiment without buying a whole new keyboard.
The short version
Magnetic switches give you adjustable actuation and rapid trigger; mechanical switches give you a wide range of feels at a fixed actuation point. Pick for how you play. Browse keyboards, or change the feel of a board you already own with switches and keycaps.