In reply to Indesign ALL CAPS button: what OT-Features does it apply? What is "desired behavior"?:
I've yet to find a need for tabular small cap figs.
This is the thread that convinced me of their necessity:
http://typophile.com/node/70865
Great to hear that! I am happy about each and every type designer who includes (proportional and tabular) small-cap figures in his or her fonts. Looking forward to a new year full of small-cap figures—happy 2013 to all of you!