What the difference between daisy chain connections and quick disconnects?

for making my own fightstick?

Daisy chains are just the method of connecting several terminals in sequence creating a single path or loop. This is commonly done with the grounds of buttons and joysticks on common ground PCBs. Quick disconnects refer to the crimp terminal that connects the push button tabs to the wire. You can daisy chain with or without quick disconnects, but the quick disconnects, as the name implies, make for faster and easier connections that can be removed in a simpler fashion.

Daisy chaining is basically taking one long wire and attaching them to several different points in order to create a common wire. Like previously stated, this is typically done with ground wires on buttons, to avoid having 6+ buttons needing separate ground wires, which creates quite a mess.

Quick disconnects are an entirely different thing. It’s a general reference towards any connector that only requires a slight tug or a push on the connector in order to pop off. You typically want quick disconnects attached to daisy-chained wiring going to each button.