In the absence of summer programs, are coursera offerings from universities worthwhile?

Taking a course, or even a few courses, from an elite school on Coursera this summer definitely won't hurt. It will demonstrate interest in the school, engagement with a subject area, and will surely help you pick up extra skills both through new academic content and adjusting to online learning. So overall, I think it's a solid choice and creative solution for your summer plans.

You can also use it as an opportunity to explore new subject areas to get a better sense for what you may want to major in! All that being said, there is no guarantee that it will boost your chances of admission. It certainly can't hurt, but it's not going to make or break an application. Good luck!!