The reason I do this is that they light so much faster at the time I'm ready to light them. This is especially nice before entertaining when I have a lot of candles to light. If they are pre-lit, I can quickly run around the house ten minutes before the guests arrive and light them in a flash! It really does help! You could say it's faster than the speed of light! haha!
Have a blessed day!
"God is light and in Him is no darkness at all." I John 1:5