Your statements are misplaced.
1) Talking about the value of serrations has nothing to do with EA; many/most manufacturers (including Land Pride) have serrations on some or all of their grapples. Artillian has serrations on the top and bottom of their grapple teeth.
2) Comparing serrations on a grapple to serrations on a knife blade for cutting is not a valid comparison, as they are different implements used in very different ways. In terms of cutting, a knife blade (serrated or not) predominately cuts by being drawn against the surface of the material. Serrations on the teeth/tips of a grapple only interact in a very limited way in that manner. The grapple's teeth can only be pushed/pulled against the material for a very short distance; the grapple teeth cannot penetrate the material/ground (unless it an unusually light material) beyond the reinforcement bar spanning the grapple teeth. Under these circumstances, is there an advantage to having serrated teeth - probably. Is that advantage significant/meaningful - probably not. Smaller material will be severed by the pressure of the grapple teeth, and items too large to be severed by pressure will not be sawn by limited serrations combined with the limited linear motion of the grapple teeth.
3) As to serrations improving the grip of the grapple, most grapples only have serrations on the teeth tips. When grasping materials, serrations on the teeth tips may or may not contact the material in a meaningful way. If you are grasping a pile of brush, only a small portion of the brush will be in contact with the serrations. If you are grasping a large object like a log, the amount of contact with the serrations depends on the size and shape of the object. I would note that EA does have an advantage in this area as their serrations extend far beyond the tooth tips. The real question is how much do serrations help. With common objects/materials, I doubt they provide any meaningful benefit. Brush piles - the serrations are only in contact with a small portion of the brush (at most the majority of the perimeter, with many only a few inches); the majority of the brush pile is held by friction/pressure against itself. Logs - probably the greatest chance of serrations providing an advantage; tip only serrations may or may not even contact the log. However, extensive serrations, like EA, would ensure contact. Presuming good contact, is this extra holding power significant/meaningful? How often do you grasp/carry a log that any serrations make a difference?
4) Serrations can also be problem with hard objects, like rocks. If you are grasping a common large, irregularly shaped, semi-smooth rock with a grapple equipped with extensive serrations, the serrations may cause the rock to lock into a position with very limited contact inside the grapple jaws. In a grapple without serrations, the rock would slide against the jaws allowing more closure and contact.
My grapple does not have any serrations, and I have yet to encounter a situation that serrations would have meaningfully improved its performance. Similarly, I have yet to encounter a situation where serrations would have diminished my grapples' performance.
So, I am skeptical of the benefits of serrations on grapples by any manufacturer - at least as it applies to compact/sub-compact tractors. A view that might be worthy of discussion, but hardly a view that should evoke hostility.