60-Degree
vs.
90-Degree
Carbides

60-degree carbide

The 60-degree point is more aggressive when new because it penetrates deeper into the ice. The reason is that more of the weight is focused on the point. That is also why it dulls faster than the 90-degree point.

90-degree carbide

The 90-degree point shares the load closer to the point. It is not as aggressive when new, but it will etch ice longer because the point dulls slower.

Another way to think about it is if what they were telling you was accurate, they'd be using surgical scalpels to cut down trees.  You need mass for durability in abusive situations. 

SnowGoer
January 1991 "Traction Action Guide"
Page 79

Varying the cross section of the exposed carbide changes its performance and durability characteristics. Ice oval racing is done on relatively clean ice, usually free of rocks gravel and bare ground. Maximum speed demands the maximum steering bite provided by a thinner cutting edge angle. Durability is usually not a problem, especially in sprint races. Thus, racing carbides use a 60 degree insert.

Cross-country racers and trail riders face different problems. Wear bars must hold up through many paved road crossings, poor snow cover and close encounters with rocks. The object here is to keep the carbide from chipping and shattering. The heavier 90 degree carbide insert is better for cross-country work because its thicker edge hangs in there better when the going gets rough....

This was written after years of industry experience with carbide wear rods!!!