The tables / spreadsheet functionality can be super helpful when you just need to jot down thoughts which lead to comparisons which lead to calculations which lead to helping you decide which path you want to go down. It's really great to not have to leave the context of what I'm doing and just open up an org mode buffer and jot down my thoughts and then come out with an answer that is backed by calculations I'm confident in. Very handy 'back of the envelope' or 'napkin' alternative!
Yes, there's a great blog post that describes how this functionality is really helpful to manage your life as lots of little spreadsheets [1].
For me that's the true advantage of Org over Markdown. It has timestamps, spreadsheets and links with citations (e.g. a DOI link type). Plus the ability to get programmatic document views using org-agenda. I can manage my whole life in a really minimal and uncomplicated way.
Of course, you can develop a really fancy Org setup. But I think a minimal one, with these features and defaults is really good enough. Plus, not hard to learn.
For anyone looking for a good place to start, here's a great resource: http://doc.norang.ca/org-mode.html#GettingStarted