org-mode tables are great. So is magit, I highly recommend it! I'm comfortable with command line git, use it quite a lot, but I also use magit a lot, and magit is especially great as a much better `git add -p`.
True, though they tend not to be very fast when they grow. (I have a table with almost 2000 rows and editing it lags a bit.)
However, I've not had 2000 lines tables yet. Perhaps a good trick is to divide them into multiple ones? Perhaps one for each category of things, if you have any different categories.
In Git, except for when adding new files, I always use `git add -p` to stage changes. And it's definitely the number one thing I do with Magic in terms of frequency. I can confirm that if you're an `add -p` kinda person, you'll love Magit.