The questions are answered in the article. The equivalence is not supposed to be obvious even to other number theorists. Most of the article is devoted to explaining "why" it works since the actual proof is two paragraphs.
Don't know what you're talking about. The article is about unproved theorems. They are described as being simple or obvious, but there's nothing obvious about
Prove that for n > 1,
divsum(n) < H_n + exp(H_n)log(H_n)
