It's a lot easier to pay taxes now on the mined bitcoins from previous years when the bitcoins weren't worth much. It's only a few hundred dollars. Then, in the future, when cashing out the btc, I won't have to worry about questions like 'where did I get the btc' 'why didn't you report it'. etc. etc. I might never be audited or asked, but to me, it's so little that it makes me feel better. Like buying insurance for my laptop. I don't need to, but it makes me feel better.

A few hundred dollars is 'nothing' in the scheme of things. It all depends what a few hundred is worth to you. To me, it's less than 0.25% of my income, so I don't mind to feel safe. It's not worth it to risk a quarter of a percent on much larger hassles to fight the IRS or pay penalties down the road.