I rode rollers in the winter throughout the '70s but got rid of them as soon as the Racermate stationary trainer stand with fan resistance came on the market. The trainer stand made it much easier to concentrate on interval training rather than on staying upright.

Riding rollers certainly makes you smoother on the rollers, but I've never seen any evidence that it's any more helpful for riding on the road than, say, riding a unicycle.

A teammate of mine used to single out and compliment guys on rival teams on how smooth they were on the bike---"I could balance a tray of drinks on your back!" When I asked him why, he said, "The more energy they waste on being smooth, the less energy they have to race against me."