A public inquiry would be able to subpoena documents. It would be able to get much more intelligence from CSIS and CSE to analyze and assess what's going on in our society, to what extent Parliament needs to be informed and to what extent the public needs to be informed. They would then address that at a high level but have a very comprehensive report.
My concern about the public hearings is that they would be, and would be seen to be, superficial. They would hear from people like the ones you've been hearing from here, but not get into the very deep issues that CSIS and others have exposure to.