Many years ago, before computers came into our homes, I did a distance learning course in horticulture. It was nothing like as long and complex as the course you've found, but now I can barely remember anything we studied. It was not as in depth as I had hoped and my final feeling was that it wasn't worth the money - I could have read some good books.
Not being in contact with other learners or staff was a big problem for me, but presumably the course you have seen will have a forum or similar online.
Your first questions would be 'what will I learn and what would I do with the knowledge? Is this to create a new career for me? Do I have the time, patience and knowledge to complete the course? Can I afford the course? And so on. On the surface it sounds good, but without seeing and exploring the standard of teaching before committing yourself, it's a huge step in the dark.
Perhaps others on here have done this particular course and can pass on that knowledge.