and you may ask "why is attachment in comments" useful?
its totally normal that people go to an event and then record voices, videos, or write points, capture events and ... . Then after coming back from the event, they want to share their files with each other in that event's page. Now there is no way, but if they be able to attache files to their comments on an event, then they can easily upload their files in their comments and share them with others.