For me, it's a historic milestone for bitcoin.
I use Lightning whenever I can.
It's easy to say what was done wrong with today's perspective, but it doesn't make sense to do so.
For me, it was a first step, and that's why I celebrate it.
Discussion
I also think it's a day to celebrate that first exchange of btc for something that added value, even if it was some pizzas. I think that first transmission was the door that opened so that other businesses can also collect in btc.