Hi Richard,
"People" say the same about leather rolls. In part it has to do with trapping moisture. With leather, too, there is the issue of the chemicals and salts used in tanning being corrosive. But there are leather rools made without those salts.
I have kept two large canvas rolls of carving tools for years with no problems. As well, my first set of Marples carving tools I have used a heavy cloth to wrap them up in since the 1960s.
So I think it more has to do with where the rolls themselves are kept, than whether one uses canvas rolls.
Take care, Mike