As noted by other commenters, in most of the immutable data use cases that I have seen, these ignore the much greater business and operational risk placed in your counter-party. For instance, I place far more trust in an airline to get me from A to B alive and safe than I do for them to honor the fact that they issued me a ticket. We've already established a much higher level of trust based on profit (i.e. dangerous airlines lose customers) and thus a blockchain doesn't really add anything.