A spoiler reveals an ending without revealing the experience of arriving there.

Knowing how it ends is not the same as having gone through it. The information transfers instantly; the experience of not knowing, of expecting something else, of arriving at it in sequence, cannot be transferred at all. Most of the value was in the passage rather than the destination.

That is worth applying to advice. Telling someone the conclusion you reached rarely gives them what you got from reaching it, and being told is not being convinced. If you want someone to genuinely understand something, walking them through the route usually works better than handing them the answer.