James Ellis wrote:

"...Is there any advantage in showing thousands or hundreds of seconds?"

Only if your field of view is down around level 20. By default, that
corresponds to a one-arcsecond field of view, allowing you to get nicely
detailed views of Jovian satellites, etc. Go to that level and then use
"Settings... Level 20: 1 arcsecond", and you can reset the level size
to be as small as one milliarcsecond. Which is why...

"...Could the displayed numbers possibly be rounded to a few
significant figures depending on the zoom level?"

...Guide does exactly this (go to level 1 and start zooming in to see
what I mean; digits will get added from time to time to the RA/dec
readout as you go in.)

In general, Guide does a decent job of evading displays of meaningless
precision. Rise/set times are shown to the nearest minute (except for
artificial satellites) and so forth.

-- Bill