There are different levels of learning and of mental processes. If you are learning information to regurgitate, an online course is fine, like arithmetic or vocabulary. If you get up into critical thinking, analysis, etc it is better to take a live course. Watch that grad students teach a lot of courses these days. Get the real thing, an inspired professor.

Much of education is a sales pitch these days, anyway. Learn the difference between advertising and information. Much of "science" is a marketing technique.