I was always taught to guard my fabric scissors with my life as well - and I have. But have also heard that cutting paper with them does not dull them.
I do know that when I paper piece I am, at times, cutting paper with the same rotary cutter that I use for fabric cutting - and usually at the same time when doing the final trim on the block - and have not noticed that my blades dull any faster.
Just my 2 cents.