I found rollers incredibly beneficial and practical for riding outdoors. You quickly become aware how each and every bodily movement is transferred/expressed in the movement of the bike, not only in holding a straight line, but in fore/aft movement. You really get a good idea of how to ride smoothly, with a quiet body, so to speak. They're also useful for a quick warm up when it wasn't real warm outside, like 5-10 minutes. When you go out on the road you find all those abilities realized in riding rollers are applicable to the road. Myself I looked at rollers more as a way to get into the rhythm of cycling than ever as a "trainer". I don't think I ever rode rollers for more that 30-45 minutes as just sitting in one spot spinning is very tedious. Even riding them outside didn't matter. I like actually moving along outdoors, with all the variance that nature offers.
A wall or anything solid to grab hold of is all I ever needed to begin. After a while a while I didn't need anything. I always take riding "tips" as "suggestions" to get you going, but I'm more of the kind of person to just jump in and realize my own inherent way. I can't say anyone "learns" to ride rollers, or "learns" anything, rather it's more like expressing the inherent abilities already inside you, conscious or not.