You could do everything Hook does by relying on a bunch of other tools and techniques, and in some cases rolling your own. So it’s one tool versus a bunch of other tools and techniques. Plus the benefit of a developer who is aggressively working to add more and more contexts – apps, doc types, etc. – to Hook.
I have one major reservation about something I personally feel is lacking with my use of Hook.
The developer loves writing and talking about Hook. This might be interesting: