If you think red death makes you useful at crota you are either bad or very mistaken... At most it helps players heal the tiny bit of damage they take in the first room. If you aren't the sword bearer, there is 0 reason you should take damage after the first room besides maybe 1 hit from boomers on the way to ogres. If you have better exotics just use Ice breaker or G-horn, you will have one or the other because xur sold IB like candy lately. Just use hand cannons or scout rifles, RD isn't needed.