If people are only using it for the correct circumstances (unconscious, vomiting, accidental over-bolus, food disaster, etc.), then it is not a problem because it is not frequent enough to cause any issues.
If I am awake and functional, and I have a choice between a bowl of ice cream or a glucagon snort, that would pretty much be a no-brainer for me.
But sure, if someone is going nuts with it and doing it everyday, who knows what that ends up doing to them.