I am sure the suppositories can help in many situations.  But, I would be very cautious in assuming that they are the equivalent of an intramuscular injection, especially in times of a true crisis. 

First and foremost:  the amount of medication that is contained in a suppository is  a fraction of what is contained in a vial of Solu-Cortef....10 or 25 mg. vs. 100 mgs.  If a suppository is broken in half, a child would be getting only 5 or 12.5 mg of hydcorcortisone.   In times of a true crisis, that may not be nearly enough medication. 

I think that the suppositories may be a viable alternative to giving oral stress doses when a child is vomitting, but I think it would be a mistake to believe that it will take the place of an injection, in situations where an injection is truly required.