It is really just a consequence tied to the Sunrise, which is already present for any spiritual being, and a lesser one at that, since it is immobilization rather than instant death. In the show it was often a plot point where the race against time became an issue, where the non-gargoyle characters could be forced to hide and/or protect the stone friends until dusk, where important objects might be trapped in a stone grip, etc. One character even made a deal with the fairy Puck to instead turn into a human during the day. In theory she would have lost the healing benefit, but she had another pre-existing deal that made her immortal, so it was moot.
Considering how many other creatures might be adversly affected by Daytime, and would thus be restricted to night-time activities, it might not matter too much. Depending of course on what the rest of the party is and what you had planned for the arc.