At college, there were so many aspiring artists who relied on heroine for stage performances. I think most of them were nervous and needed a boost to perform well. None of these people made it in the music industry today; I feel it was a waste of time and money consuming substances that could not help them get the career they desired.
Some people want quick fixes for their predicament. Little did they know that they are only causing more problems. In the end, the very substance that they thought was helping them actually caused their downfall. It's really sad.
Mara pretty much summed it up. They can't think of any way to overcome their fears and difficulties so they resort to something that, although in the short run will help them, it will destroy them in the long run. The problem is that they are oblivious to the long term consequences of their actions, this is applicable to almost every instance of someone using drugs for the first (few) time(s). They just need to be educated of the negative consequences of their actions so that they don't do this. For example, their managers or directors should tell them that drugs are no way to overcome a fear and that there are plenty of other, better ways to do it.
Their confidence level is usually very low so they turn to the heroin, which gives the boost to make them feel that they are in total command. A heroin fix before a performance is like a magic wand to these persons.
Maybe they took heroine to help them deal with the pressure, or to get inspired. I've heard it from many wannabe-musicians that all the best musicians take drugs so that they become inspired and write their hit songs. Perhaps this was true at some point, but I think the modern music industry is a very controlled environment, where most of the top songs are written by a handful of people...who stick to a pre-defined formula. The drug addicted musician will probably burn out sooner or later, and won't achieve success. Or if he/she is successful, their drug issues will catch up with them and cause problems in their personal lives and careers.
I really never think of heroin as a performance drug. I know people can't perform while on it because they are so relaxed and don't care about anything. Think Amy Winehouse when she is all drugged up and can't remember her lyrics. Everyone says she was drunk, but I am sure she was shooting up as well.
This is also true with some writers and artist/painters. Some say that they are more inspired to write when they are under the influence. They either use drugs, smoke marijuana, or drink alcohol. Well, I don't really know about that. The only alcohol inspired prose that I was able to write was the lengthy text messages that I sent to my ex. A mistake that I don't care to repeat.
Yes, you are absolutely right. Just relying on heroine and giving out a wonderful performance would not make anyone a successful singer for life. You must have your own 'inner' confidence without any drugs and that can make you successful. Heroine for stage performance is not at all a good idea.