Clashes are bad, whether for big films or small, as clashes mean that the revenue of the films released on a particular day would be split between the films released on a particular day, which would be a lot less than the revenue a movie would get, if it had a solo release.
While big films somehow seem to be able to manage in the end, the same cannot be said the same about small films though, as they have a restricted time in theatres, and a smaller budget, when compared to bigger films, which would mean that they would suffer terribly, if many small films release on the same day.
This seems to be the case with many films releasing in September, as a lot of small films are set to be released on the same days. Given that neither of these films have a huge buzz surrounding them, it could be a huge mistake for films to be clashing with each other on the same day, with respect to September releases.