Finding mementos like that can be fun and, as you say, a great conversation starter and opportunity to talk about your adventures.

But collecting souvenirs becomes impossible or at least very impractical for those of us that travel full-time. I know full-time travelers that collect stickers or patches or other small things but even that becomes difficult if you travel long enough. For this reason I chose to only keep digital pictures and try to avoid buying or picking up anything that I do not need or really want that will add value on other ways.