Rolled edge coils smoothly
Resilient and strong willed
Beware flaccid yarns
Technically speaking, it doesn't matter precisely how you cast on or bind off (as long as you do it loosely), because the very edge of the fabric is hidden in the roll, but there is still lots of scope for exploration.
Clearly, swatching with the chosen yarn is critical - left to its own devices, how far will it roll, how determined will it be to stay put?
Round knitting has circumferential tension to hold things in place... like folding back a cuff:
Which could negate the roll, as easily as preserve it. The tension will be greatest when the circumference is smallest - so the effect would be greater at the border of a wrist than a hip; more prominent stretched (like a hat band) than relaxed.
The rolled edge can solve the problem of cast on/bind off tension for an elastic edge (as long as you cast on or bind off the roll loosely) and provides a more robust edge surface for heavy wear (TechKnitter has a great treatise on why this is so.)
It resolutely maintains the stockinette gauge inherent to its nature, however:
Which makes it a prominent design feature, rather than an unobtrusive beginning or end. Will the ribbing spend its functional life around a head, fully expanded to match the roll, or is it destined to stretch over a heel or hand, snapping back to hug the smaller body part?
TECHknitter (Really, that's all I could find. Most knitting resources seem to treat this as a sort of a default, no-brainer edging.)
Anything to add?