Of course it will do good; the point is: we can't know much of history that we havent' lived through.
Sure we can. What makes you think we can't? Have you ever taken a history class? Have you ever watched a documentary on history? I mean, we obviously can't know every detail, but we can know enough to have a clear picture of the era or person in question.
Any "evidence" for any historical figure can easily be fabricated.
That's not even remotely true. There are millions of ways to detect hoaxes, as has been made evident by the fact that researchers and historians have summarily dismissed plenty of them.