Why? Not a single point of issue. Given now that it has now 25% market share, it's a high profile target, and given he short cert lifetime aggressive updating is necessary meaning you could receive a underhanded cert in case someone gets access to the high profile target. If Let's Encrypt is not a startup and doesn't plan to make money, then there should be no problem to release the whole service as DEB/package so that every big hosted can run a clone under a different name. Or is LetsEncrypt in the business of gathering analytics and selling the usage data? I think no.