I see on ebay and elsewhere proof coin rolls being sold quite commonly. I am trying to understand this. Are there people who like collecting proofs in roll form? Do people believe it is a hardier or more practical storage method for proof coins? Or is there some profit motive involved, a la 5 rolls bringing more than the 50 sets which filled them? Or some other reason? for modern proofs, I am concerned about rim damage that I would imagine rolled proofs may incur?
Ok I can answer this one. Lets take the ATB quarters for example. From the US Mint you can buy a roll or bags of P or D circulation quarters but you can also buy the "s" quarters which are not intended for circulation prices run about $19 +shipping a roll or $35+shipping for a bag of 100. This years "s" quarters are already selling daily on ebay for between 1-8 dollars EACH (average sale when I last checked was about 2.50) on the other hand I myself buy bags of the quarters searching for the new errors I might sell a few if they break 10 each but for now they part of my hora's nest
The previous answer has nothing to do with the question. Those S mint ATB rolls are circulation quality, not proofs.
To the OP, I don't think anybody assumes keeping proofs in a roll is the best storage method. On ebay, you see collectors and dealers liquidating modern, normal-grade proofs in droves. They buy a bunch of proof sets, keep the PR-69 or PR-70 ones, and sell the PR-68 ones or less in rolls. They're getting rid of lower grade inventory they'd rather not piece out. It's easier and takes less time to sell them in rolls.
This is essentially accurate but might be misleading. They cream off one or two coins per roll (if that many) but they also cull out three or four coins per roll. In other words the average quality of proof rolls tends to exceed the average quality of proof sets. The value of the coins in proof and mint sets often exceeds the value of the set and can be much easier to sell. This is what drives most of the set dismantling. There are other factors and other reasons to cut up sets.
I did it with a bunch of silver proof sets a little while back. For whatever reason, they were fetching a higher price on FeeBay in rolls and they were a lot easier to sell (fewer lots) and a lot easier to ship (less volume).