I really hope it matters if you use these powers or not.
Bad idea:
- It makes no difference if you use it or not. Not using it means you just miss some abilities.
- At some point you are forced to use it to progress. They devs really want you to see those cool things they created.
- You get the bad ending no matter if you use them or not. To get the good ending you must use it at specific points to get specific results.
good idea:
- It makes a difference if you use it or not.
- If you use it at least once you can chose if you follow the advice of your dream person or not.
crazy idea:
If you use it often and you follow the advice of the dream person you will turn into a mindflayer but you keep your personality and your class.
You have to stay hidden or use disguise to get near normal people or they will attack you. Some may detect you even when you are disguised.
But you gain strong powers and you get new options when interacting with cultists or other Illithids.
PS: I did not use it on my first playthrough and I was wondering what this dream person is that everybody is talking about.

Prof. Dr. Dr. Mad S. Tist

World leading expert of artificial stupidity.
Because there are too many people who work on artificial intelligence already