What’s remarkable is the easiness with which they could be detected if some resources are spent. And if a planet like that exist, it’s one of the top destinations for future interstellar probes and eventually human craft, because of the short four light year distance.
I’ve always found exoplanets very fascinating. They represent truly new knowledge that wasn’t yet available to us only a few years ago. If the graph below is to believe, the trend is promising, and in only a few years we might have even publicly notable results about Earth-like planets.