Low-latency ink (a.k.a. zero-latency ink) allows ink to appear on the screen as close to the pen tip as possible. This provides an extremely natural writing experience, much like if you were writing on paper.
While we do not have a definitive list of devices that support low-latency ink in Squid, it is our understanding that low-latency ink is supported on all current and future Chromebooks with an active-pen digitizer (with the exception of the Samsung Chromebook Pro). Whether a device supports low-latency ink is up to Google and the manufacturer. Squid will support low-latency ink on any device that has the capability.