That's very true. The one I am using now is a regular thickness knobbed mat but quite stiff; there's no way I can roll this into anything more slender than a 1-metre-thick cylinder. I suppose the soft variety in tubes will offer as much protection as Saran wrap, to be honest. Bear in mind, though, that the mat is protecting the carpet from your feet as well, so, ensure there is enough of it passing underneath your desk, too. Replacing your mat is inevitable, so, no need to dig deep into your pocket for a fancy one, either.