I don't know how I really feel about these in the context of homeschooling. But I've noticed that more and more vendors are offering them.
Some of it seems contrary to the point of homeschooling- learning at home at the child's pace, with parental involvement. It brings in outside deadlines and teachers and expectations.
Is that really bad though? I don't know.
I just know that it's different and part of the evolving world of technology and homeschooling. I'll be watching with interest.