So that tournaments with long time control take even longer than seven years to finish?

I personally would never use that option since I would be giving up equity.

You have all the "equity" you will ever need in the first move blocked on the bar, when you can double, or (hopefully) opt to forgo doubling while blocked. I find it difficult to imagine a game where you are blocked on the bar, and would not want to double on the first throw, but (presumably when your opponent has improved his position significantly) would want to double later. If there is something cunning and subtle that I have missed, that would increase my "equity", please explain with an example.