The addition of drugs sort of pulls back the curtain on what other things may be just under the mark, lurking beneath your "default" consciousness.
This reminds me of one my favorite quotes from Westworld (HBO, 2017)
"There is no threshold that makes us greater than the sum of our parts, no inflection point at which we become fully alive. We can't define consciousness because consciousness does not exist. Humans fancy that there's something special about the way we perceive the world and yet, we live in loops as tight and as closed as the [robots] do, seldom questioning our choices - content, for the most part, to be told what to do next." - Dr. Ford (character)
One of the things I really love about marijuana is that while it mentally alters your state, it leaves you completely coherent, where you can still be perceptive and reflective. For me it's like a deep, consistent meditation if I relax and really focus on how I'm "thinking." Perceptually, at least personally, it really feels like there are mental facilities that suddenly become "communicative", a higher (no pun intended) mental state. If I dose right I often use marijuana to reflect about how I'm living my life, a social situation that needs attention, a hard problem at work, or sometimes I just really really love listening to music. And I have to say, if you've never listened to music while high, you truly are missing out on an experience.
All this is basically to say I totally agree with your statement about "pulling back the curtain." I personally consider it useful, it's often nice to have a different perspective on a problem. It's helped me out a lot, I think.
What basically happens (among other things) the feed from my subconsciousness that sometimes suggest ideas out of blue or solves problems becomes much, much stronger. Sometimes I can't even manage to type all of those ideas/todos into phone, they come so fast. The only issue is, short term memory impairment also makes them fade away pretty quickly, so sometime it looks like a race to record it all.
I think this is also the scientific consensus. "Consciousness and the Brain" is a good overview of recent studies on consciousness, and piecing together the results. I've just started reading, but so far I'd highly recommend it.
Isn't it obvious?