Depends really. If there are very big effects on the gameplay from playing in night, it's nice that it passes soon enough for me to get the stuff i want done done before i have to go to bed irl. However, if the game lets you wait or sleep that's not much or a problem.

20 minute days are way too short. I think a full 24 hour cycle should at least take 2 hours.

And pumpkin, even if the game had one hour lasting one hour, the game wouldn't necessary sync the time with your own. It could be made to only make time pass while you're actually playing, so the first two nights you play it would be day, then the second two nights you play it would be night.