Thinking about it, this probably also gives Apple a ~fairly accurate set of usage stats for software.
All they'd need to do - and it's very simple - is count the number of requests of each given hash lookup.
Since they know the hash for each of their own executables, that gives a direct count of "most used" through to "least used" programs.
Not sure if they'd have the hash for third party executables though, to know what the given hash request corresponds to.
If they receive the hash for 3rd party executables when developers sign things, then Apple seems like it's able to generate usage stats for their entire OS and 3rd party app ecosystem.