Just got back from the Eastern Conference, and Toshio Odate discussed roller jigs during his sharpening presentation. He thought they gave you TOO sharp of an edge - it will be too fragile, and chip off (at a very tiny scale) thus dulling your chisel. He felt that using your hands without a jig gives you a slightly imperfect edge, which actually lasts longer. We watched him do this with a planer blade, and then he planed some pine for us. The shavings were so thin, you could read fine print through them! CB.
I think that any sharpening technique, done well, can
produce an overly fragile edge, but I don't think it's as simple a matter as how acute an edge has been produced (nor do I suspect does Odate think such).
An edge that is a little more obtuse, if smooth, will stand up longer than a very acute edge, that is true. An edge made quite acute can be dressed, or 'jointed' on the stone, to reduce the amount of acuteness, and to clean up raggedness on the edge. You want to find an elusive balance point between as acute an edge as possible and one that will stand up as long as possible, and this is very much a case by case situation, given different steels, and different woods, and different phases of stock preparation/finishing. For hogging off material, such as when scrub-planing, a more robust edge makes sense, while for that finish pass or two, pushing the edge towards greater acuity, at the expense of durability, makes sense. Some steels tolerate a thinner edge than others, and some steels can be refined to a thinner edge than others. I'm not going to get into specifics.
If the edge left after sharpening is at all ragged (this can be seem with a pocket magnifier sometimes, or felt by running the your finger nail carefully against the edge, or by looking at the edge in the right light), then it will tend to wear faster. This is kind of like having slightly rgged finger nails that catch on some fabrics.
The edge raggedness can be produced by improperly removing the wire edge produced through working the bevel on the stone.
There are ways of dealing with this problem, and I think I agree with Odate's thoughts insofar as the roller jig limits the range of techniques that can be applied to flattening the blade, back and bevel. A jig also is a one-step removal from intimacy with the process of sharpening, as it removes some of the feel transmitted from the blade rubbing on the abrasive. This is less a factor in one-piece blades, but quite important with laminated steels, such as are found on Japanese quality tools and some very old western ones.
I don't use any sharpening jigs myself, but recognize that they do allow for rapid and controlled work to change bevel angle. The roller jig can help some people with simply rough-patterning the physical movement of rubbing the blade back and forth on the abrasive. And, if person hasn't developed really good control over the tool when sharpening, the roller jig can definitely facilitate the sharpening of some of the more challenging tools, like long handled chisels with small bevel surfaces. The greatest flexibility in technique is gained by learning how to sharpen freehand, IMO, just like learning how to ride a bike without training wheels.
Sharpening is the foundation of hand tool use, and while the idea of sharpening might seem basic, there is a lot to it. It's not something you just learn and then are done with it - it's an ongoing exploration.
Any finish shaving, I might add, ought to be thin enough to read a newspaper through. Not all woods yield that type of continuous shaving however, but pine certainly does.