I use formative as a way to monitor student productiveness when I am out of the classroom. When I am at home sick, I have watched students working around the time they should be on that activity. I am then able to see who was working on what they needed as well as assess their knowledge. I use Time for Kids. I include photos of the article as well as comprehension questions I would want them to answer if I was there. For math I reviewed work that we have done before. I have embedded videos as well as giving instructions as well as them completing work.
It has been a useful tool for me when I have been out.