Many DX-ers (MW DX-ers in particular) are concerned about the Excalibur's ability to show the exact frequency down to the hertz. While most SWLs will be indifferent about this, quite a few are monitoring a station's offset from it nominal frequency, and it is also helpful for tentatively ID-ing stations (assuming their offset is reasonably constant).
By zooming in the demodulator panel and by using 1 Hz RBW, monitoring offsets is indeed possible, as illustrated above. Two stations are visible (and audible) on this screen dump from 999 kHz, a Russian-speaking station on 999.008, and a presumed Arabian station on 998.992 kHz. Prior to monitoring, I calibrated the Excalibur using a tone from the signal generator on 1000 kHz. Of course, in order to monitor offsets in the range of 1-5 Hz, the readout must be exact.