Lighting a candle on יום כיפור

2 מנהגים both same purpose, פוסחים נג:, both מנהגים are for the purpose of מניעת תשמחי as it says ועמך כולם צדיקים ירשו ארץ the question is only the tactics is it more effective by having a light on שאין אדם משמש מאות לאור הנר. Or is it better to not have a נר so not to create desire. 

We have taken this concept today and went off the rails. Today we say that it is better to allow תשמיש for שלום בית purposes. Then we will go and quote ועמך כולם צדיקים ירשו ארץ. To justify acts that are against the Torah but that are, in our perverted minds consistent with the spirit of the law. That is a slippery slope....