I usually do a bit of one and some of the other, meaning that I both fold and roll. I don't see a prob with stuffing into a sack other than Biker's observation.
The greatest influence in degrading a synthetic tarp is probably exposure to UV radiation which causes the fabric and coating to take on that crinkled appearance.
The only way of preventing that is to go out only in lousy weather... if that's what turns yer crank!
Off with my hammock and tarp for a couple of nights midweek to a bonnie -and forgotten- wee Fife den that contained a main road when General Roy conducted his Military Survey in 1747. The fact that it was once a main road is probably the reason for it being unmolested since the course of the road changed to higher ground about 200 years ago.
It's a place with a good feel to it, cool, crystal water and more firewood than ye can shake a stick at...
Cheers.