Having a standard is an effective form of communication when you are dealing a diverse (time or space) membership working in the same problem space. It's saves time, saves effort, and improves communication.

Think traffic laws - they are a set of standards that allow you to know what the driver next to you should do. If those standards weren't there it would difficult to drive, you would have to graft on other forms of communication like hand signals, or curse words to drive safely. What makes them work (when people follow them) is they are reasonable (at least most are), there are not a lot of objections to them, and they are codified and easily obtainable.

PBP is a reasonable set of rules, the community as a whole doesn't have a lot of objections, and it's codified in a nice package, so employing it as a standard makes a lot of sense. It saves time, improves communication, and prevents drunk coding accidents.

That being said, PBP is not the be all end all nor should it be followed blindly, but as set coding standards it has a lot going for it. If PBP (or a subset of it) stops making sense in your organization then don't use it.