I don't like changing my strings often because it's a hassle; and with Elixirs, I don't need to! They can last up to a third of a year for me under regular play which is great because I play daily and man can these things take a bashing! Also, I like how smooth and silky the strings feel under my fingers; it makes for quicker, more eloquent playing, I find.
I can trash most strings in a week, no tuning held and sound awful. Not these. I get between 1-2 months from these, which is incredible. I absolutely swear by them. And no they don't "deaden the sound"