1. Fun
2. See people who dress up as people you like
3. COSPLAYERS!!!!!
4. VOICE ACTORS!!!!
I might head to Zenkaikon 2020 next year as these three people
Day 1: Karkat Vantas
Day 2: Post-Dragon Kaneki
Day 3: Jyushimatsu Matsuno
If you are going, look for those characters.