As you said, both possibilities are there.
I think we can be deluded during psychedelic experiences (and in normal life too!), but there are definitely long lasting realizations and ideas that can appear during a psychedelic experience.
In the end, it's all up to you and the very important process of
integration . What do you bring back from your travels, that can help you or others?
Not all experiences have to or should turn into something productive in a measurable way, but it's important to keep a healthy balance in mind.