Oh, sorry ... I didn't mean to imply that that was what you were after.
But using th same registry setting mentioned in that article allows you to see
loaded add-ins and, if they're your own or at least unprotected, to edit them
in place.  It's a FAR faster way to test/fix add-ins than opening the PPT,
saving as PPA, testing, wondering what went wrong, repeat until hair falls out.

With the PPA open, you can set breakpoints, SEE what goes wrong and usually do
a test fix on the spot.

The only hitch is that you can't save the code from the addin, though PPT
pretends to let you do so.  Instead, once its' fixed, copy/paste it back into
the source PPT, or export the modules and later import them back into the
source PPT.

I'm babbling again, aren't I?

My best guess at an answer:  

Because.

;-)