Quick-release systems are not a recent invention: already in the Seventies certain sports calibers featured integrated lugs to avoid the traditional spring bar. What has changed over the last twenty years is the proliferation of proprietary patented systems, each incompatible with the others, which make strap changes quick but lock the user into the manufacturer's ecosystem.
The mechanical principle is always the same: a pin or tab integral to the strap locks into a recess cut into the lug or end link, and releases by pressing a button, a lever, or simply pushing the strap in the axial direction. Omega uses a rear button that releases the pin from the head; IWC with EasX-CHANGE works on a recess cut into the inner lugs; Hublot with the One Click system integrates the snap mechanism into the lateral flange of the case; Cartier with QuickSwitch acts on the terminal links of the bracelet; Panerai with the PAM Click Release frees the connecting bar with a lateral press. Leica, on certain photographic models, even incorporated the release button as an aesthetic reference to the camera's shutter.
Drilled lugs, that is, through-drilled lugs, are instead a different and older approach: the hole passes through the lug from side to side and allows you to secure the strap with a threaded pin or with a larger diameter spring bar, without the bar being able to slip outward. It is not a quick-release system in the strict sense, but it reduces the risk of accidental loss and facilitates replacement compared to a blind lug. It was common on sports chronographs in the Sixties and Seventies; today it is found on watches like certain Baltic models that reintroduce it as a conscious technical choice.
From the workbench, the practical problem with proprietary systems is the availability of spare parts over time. When a manufacturer updates the platform, the straps from the previous generation often do not fit the new case. Anyone buying a watch with a proprietary quick-release system should verify whether that seat is still in production and whether there is an adapter to the standard spring bar: in some cases there is, in others there is not. Catch springs, retention springs integrated directly into the strap, are an intermediate solution that does not require case modifications but still offers a tool-free attachment. They work well as long as the spring maintains tension; after a few years of heavy use they should be checked.