Originally Posted by
canadiancow
I don't even consider it to be insurance... it also drastically increases your upgrade priority (and since downgrades should use the opposite order...)
Very much this. On a Lat fare Intl the other day, my J upgrade was only #8 or 9, which was driven by everyone in PY being ahead of me. I ended up in PY, but definitely a good reminder to book PY if you want a hope of J.