20 weeks of 40 hour weeks is fast. Exams and assignments are going to consume some time and you probably won't know every nuance of a course even if you've taken a different and more rigorous variation.

It also probably depends how big a deal the 4-year degree is to you. There are other options like edX MicroMasters that may make more sense (and it wouldn't shock me if they carried more cred in at least some circles).