I think there is no one size fits all. Donna and Matt Jordan use lines on the mat and Matt has marked a giant board with widths that he cuts. His precuts are big sellers so guessing they are accurate. I watch a lot of different quilters on YouTube and some use mat and some use ruler. If I am making something that is forgiving I use the mat. For more precise I use the ruler. If someone has invested a lot of $ in rulers by all means do that. But I don't think we all have to do what everyone else does. Do what gives us the best result.