There are two reasons to add ties to the game:
1. Some professional leagues (in particular KBO and ***) have ties; and
2. Ties were a regular feature in the days before the majority of ballparks had lights (pre-1940 or thereabouts).
Ties can still occur in MLB, but they're so rare (I think the last one
was in 2016) that the average baseball fan would be excused for thinking that ties can't happen any more.