it's more or less to test the substance on tv, or to see how good it is IRL I assume.
it's not like you're walking around slobbering everywhere like you just got your wisdom teeth removed. It's like a hey there's not enough left for a rail... let's make use of it.
Again, I never got into any hard stuff so I dunno.
I smoked a shit ton of weed when I was in college and, I tried Shrooms 3 times... I never once tripped or enjoyed what was happening.