I have never once used a suicide move as a part of battle strategy. When I was training a Bagon in Emerald, I took it to Victory Road with an EXP Share and had a Graveler that knew Self-Destruct. I would use it to take out some of the really strong Victory Road pokemon, but when it fainted, my Bagon got tons of EXP. That's the only time I'll ever use that. I HATE when my pokemon faint, I treat them like gold and I want them to have max happiness just because I feel it reflects on my skills as a trainer.