Filters, especially 9 mm charcoals, are intensely popular in Europe, less so in the U.S. I think they are useful -- though I don't use them often -- for doing trial runs on very strong blends, and for when you will be smoking more than usual, like a pipe show, a pipe club, or a pipe shop. I drag my feet on any additional supplies to be bought and maintained for pipes. I think there is a tendency to smoke more bowls with filters. But I don't feel any prejudice about smoking with filters. If others like them, that's fine. I keep them around should I want them.