I put a few things. It read exactly like this -
"Gender presentation, family disassociation, sentimental value, common (non-legal) usage."
Reason SPAM!

Over here we have an interview, and I got though mine with no issues. One look at me, one look at the names involved and out came the approved stamp.
We may go through our lives without meeting another TS face-to-face, but they work at a place where we all eventually end up going. We're not as unusual to them as we think we are. It's just easiest to tell the truth. It is a very valid reason after all.
Be careful with "common usage", I've heard from some people with that as their only reason they've had to
prove the usage (store loyalty cards, library cards, letters from friends, etc).
Different countries and all, YMMV, but giving a reason seems pretty universal.