I'm aware that the original poster was talking about a rigid fork, but all rigid forks aren't created equal.

For instance, the first bike is an old Peugeot and the second one is a Norco Monterey with disc brakes. The fork of the first one is slimmer and has a gracious curve near the bottom, so it will follow much better the irregularities of the road than the fork of the second bike.

There are two effects of that:

1. On a bumpy road covered with snow (mud or sand), front wheel adherence will be better, resulting in better control of the bike (I tested that one personally)

2. Riding the bumpy road or a gravel road with a flexible fork will be more comfortable on the hands.