This is because if your protagonist is not challenged, if they're not forced to confront obstacles.. then what are they doing, and why do we care about them? (Hint: We probably don't.)
The Monomyth, (The Hero's Journey) is probably the most popular character arc in fiction.. and it teaches that the Character at the beginning is the opposite of the Character at the end. They are weak, ordinary, small, afraid, powerless, fearful, full of self doubt.. at the beginning.. but at the end of your arc they are strong, unique, powerful, and confident.
It is the course of this change that excites and involves the reader.. your character doesn't become superman during the course of your story.. in fact their moment of power and strength may just be a brief moment in time.. it may even be borrowed from another character, but it exists to help them save the day.
It doesn't even have to be physical strength.. it can be mental strength as they figure out the clues.. it can be magical, ("Neo, you're the ONE!").. it can be in whatever manner you choose to tell your character's story.. just make sure they start out weak and end up strong, and then show the reader how they became strong. That's the fantasy we're all dying to read, to escape our ordinary worlds..we want to watch someone go from how we are.. to how we'd like to be.. from weak and ordinary to strong and extraordinary.
So.. at the end of this blog challenge, here is my advice.. remember to move your Zero to Hero.. in whatever manner best fits your character, have them fail.. a lot.. along the way, but ultimately have them succeed in a manner that we didn't see coming.