A computer science degree means you've spent 4 years learning computer science, it doesn't mean you know anything about software development. In fact, at a university with a good CS program, it almost certainly guarantees you know nothing about software development: UC Berkeley's CS program has a single optional elective on the subject of software engineering.
Now, there is a high correlation between computer science aptitude and software engineering aptitude, but I wonder if it's just because we've conflated the two because the field is so young. I believe that one can be taught without the other, and that's what we're seeing with these academies.
Consider: on one side, you have someone who spent 720 hours over the course of four years learning Delaunay triangulation and LALR recursive descent parsing, but has never written or architected a greenfield application from scratch.
On the other, you have someone who spent 300 hours over eight weeks building applications, being exposed to good industry practices, learning how to deploy systems, how to use source control, how to use an IDE. Maybe afterwards, they could spend two weeks covering fundamental theory.
Let's be honest, when I go out to interview I do the same thing anyway.
As an employer, the latter would be more immediately useful to me. So you're right, the comparison is ridiculous, and an intense course is not a substitute for a multi-year degree. But stop and ask yourself: is a CS degree the right criteria for admission into the industry in the first place?