It is. If it's a arc nightfall, thunderlord brings down half of any bosses health. If it's void, I have an old void machine gun that brings down about half of any bosses health. If it's solar then gjallarhorn would the obvious choice. I sometimes would pull out a gjallarhorn during a boss fight when there isn't a shield or burns but most of the time I would use against all odds or hunger of crota for that job.