Hey, Mike Arpaia here. You're totally right in that the SQL interface is very similar to WMI. Some core differences with osquery are:
- it's cross platform and supports many *nix operating systems
- adding new tables is very well supported via a simple API: https://github.com/facebook/osquery/wiki/creating-a-new-tabl...
- several tools and utilities exist to leverage the power of SQL at scale (osqueryd is a full operating system instrumentation tool which allows you to use SQL to instrument your whole infra): https://github.com/facebook/osquery/wiki/using-osqueryd
All in all, WMI is great, no doubt about it, but osquery has a few unique features which make it a cool, interesting product that you can use all across you internal infrastructure.