I think you need to take a step back and look at the complete value proposition that you put forward to employers, and people that you network with. The O'Reilly course could be useful to almost anyone because it has the university backing, but it is completely dependent upon how you use it. Programmers love to talk and think in absolutes but the world is not really like that. If you think it is then you haven't seen enough of it.
You don't provide enough context, but I'll assume that you don't have a computer science education. Employers may use a CS degree as one of their primary filters. You need to mitigate this filter with equivalent experience or education in different areas that can apply to their domain.
I could see a number of benefits to the O'Reilly course that help in this area:
- It is run by a reputable technology education organisation. A lot of developers swear by O'Reilly books so why should the courses be different?
- The person running the course has experience at a leading university. There are different kinds of instructors but the best tend to have some experience in universities and corporate environments.
- You will reinforce the quote "I know python". Do you really know it? Through a course like this you will fill in gaps in your knowledge. That said it is important to read the syllabus and contact the instructor ahead of applying to the course to avoid wasting your time with basics that you do know. (again some more context would be useful here in your question.
- It demonstrates a focus. Assuming you are really interested in working with Python it shows that you have been able build on this interest and take it to the next level. This is more achievable than trying to do a more academic course and then struggling to be focused because you were only interested in the programming and not the mathematical aspects of CS.
Building on this course with contributions to open source projects or other tangible examples is only going to help you. This shows that you realise that you need theory (the course) and practice (course exercises + outside projects), and gives you something to talk about with recruiters.
There may be some other certificate options at universities that you might want to look into if you feel that you need to do something a little more academic. It seems like these are targeted towards those with some sort of undergraduate degree so I've no idea if these would work for you.
It seems like many people are conditioned to discount learning that is not done through an established university. This is especially true when dealing with recruiters and managers who have some distance from the actual job at hand.
Many people would say that they just want someone who is capable of doing a particular job. But when it comes to actual selection they will use filters that they understand further reinforcing this problem. eg. they like to hire from the same universities. This turns out to be good and bad from a shared culture through to problematic group think.
This is important stuff to think about when you research employers as you want to make an impact on the right people. If you don't think you'll get past the filter that a recruiter places in front of you, but think you can make a difference for them then you need to find a way to get the people who will. These are the people who are more likely to appreciate a certificate like this.