A rotary blade rolls over/through the fabric.
A exacto knife would be pulling through the fabric.
I don't think you would get a good clean cut.
As well as the safety issues as mentioned.
A rotary blade will cut through atleast 4 layers of
fabric with no problem. The blades do get dull after use and needs to be changed periodically, depending on how much it ts used. I think the most used size would be the 45 mm.