I use Toyo 6x7 roll film holder on a toyo-field camera. The reasons are: 1. my 4x5 lenses and shutters are better than my medium format gear. 2. movements. 3. a film holder is lighter than a medium format camera with it's lenses and backs. 4. the relatively cheap cost per shot of 120 roll allows for more experimentation (This might not be of great importance for those who have been using movements for decades, but for me it is important).