I agree with Emily on this one - the question is really to which extent does the online courses complement the rest of your profile.
To answer whether using the courses strengthens your overall candidacy or not, I would ask myself how your course fits in the overall skill set demonstrated in your CV if I were you.
If you're for example a non-business background and have used the finance course to prepare yourself for a demanding business/finance job or business school outside your comfort zone, it could help to show your dedication and underline that you're determined to accept challenges to reach your goals.
On the other hand, if you have other areas in your CV where you already show business affinity and experience, I would see it differently. I might even ask myself whether an additional display of an extra business course may not even have an effect of "belittling" your other business achievements and experiences - as always with the CV, the context counts here.
To your second question: to better leverage the experience received, nothing stops you from providing a small comment at the end of your course description that describes exactly what you took away for your career, e.g.: "gained key experience in accounting and balance sheet analysis, leveraged in subsequent M&A assignment".
Best of luck!