Here’s my take on this.
A SIM card tracker realistically provides the general location of the device using cell tower triangulation, not exact GPS coordinates. This means you’ll get the approximate area—which is more accurate in cities with many towers and less so in rural areas. It’s effective for narrowing down a search zone. Some services may also display network carrier details or the IMEI of the phone the SIM is inserted into.
Regarding the timing, it’s best to think of it as near real-time rather than instantaneous. There’s usually a slight delay as the location is requested from the network provider. It’s less of a continuous live feed and more like a series of location updates or ‘pings’ whose frequency can vary.