It doesn't really matter how irrelevant something really is, being one of the first to do it almost always gives you a bit of an ego boost, especially in a social game. I admit to being vulnerable to that feeling, as well. In WoW, for example, I was one of the first on my server to have a Dragon mount and a Mammoth mount. It's kind of embarrassing to look back now and see how proud I was at the time but I'd probably do it again if I had the chance.
I understand that as well. When FF14 Heavensward released, I rushed the expansion during the 1 or 2 days early access (for people who pre-ordered). It was a great feeling to arrive in the new late game city with almost no one there yet, and people trying to understand together what we needed to do in each new dungeon instead of having as usual at least one player knowing the strat perfectly. It's a much more enjoyable exploration if you're one of the firsts!