Occasionally, there are surprisingly heated debates on this board about the celebration pins. However, when calling for resort or dining reservations, I was constantly asked whether we were celebrating any birthdays or anniversaries. One of the many reasons for our multi-generational trip was my parents' 45th wedding anniversary, which did not fall on the dates of our trip. They proudly wore their anniversary pins and had many lovely chats with CMs because of it.
Disney definitely encourages people to wear the pins and I've even heard CMs offering them, saying "surely you're celebrating something!" and maybe writing "school's out!" Or "got my first real job" on the Celebrating buttons in sharpie.