I like to do that every so often to remind myself of what it must have been like in the days before electricity, at the time of the Prophet sal Allahu alayhi wa sallam, and in modern times in places that do not have stable supplies of electricity.
Try it, it’s a humbling experience, and reminds me to be thankful for the blessings great and small that I take for granted every day.
I remember after I converted to Islam, one of the awe-inspiring thoughts that would often come to my mind was the image of Muslims all over the same geographic locality and community, people I didn’t know and have never met and maybe a few that I did know, in their houses and in masajid are praying at the same time or in the same period of time, leaving off worldly matters to turn in private conversation with their Lord. Subhan’Allah.
Another nice thing to do is to call someone at fajr time, not to chitchat but just to say salaam, alhamdulillah for another day, or asalatu khairun minan nawm – prayer is better than sleep. I think I might start doing that again, so if you’re in my cellphone phonebook, don’t be too surprised or angry with me if I call you at fajr time.