The more an asset matures, the less it acts like a lottery ticket -- for better and for worse. For most investors, who prefer compounding to coin flips, it's a good change. The catch with Bitcoin (BTC 0.62%) is that its spectacular past gains are easy to remember, and they have set expectations unrealistically high. There's some solid evidence suggesting the coin's returns are compressing over time. But does that mean it's too late to buy it for the purpose of long-term holding? Based on information compiled by BitBo, a cryptocurrency data service, with each four-year halving era, Bitcoin's returns -- as measured by ... (full story)