You can't really compare rune magick to a candle. You don't need candles to use the runes. A candle is used as focus, and is a tool that does not hold any magickal property unless you believe it does. Runes on the other hand are symbols and sounds of power. They hold their own magick and meanings that are tapped into through focus. Yes, you can use rune magick and no candles, but it shouldn't be seen as a replacement, it's an entirely different thing.
Be careful when using runes in magick, if you don't have a deep knowledge of their full meaning and power, you could do more harm than good. This is the same for using anything with power not of your own, such as planets and spiritual beings. For instance, you wouldn't just throw a mars symbol on your altar in place of fire/a candle because the power of mars is far more complex than fire alone, and will have influence over your workings that may be undesired. When using a candle we instill our own influence over the meaning of that candle and the energy therein. So it is 100% under our own direction.