Unless you have a small (very small) diameter pulley on an item the AX variant to get the notches doesn't help in any way
Solid belts wear pulleys more slowly than interrupted (aka cogged) belts, such as the AX you refer to. Link belts would in theory have similar wear issues, because they too have an interrupted surface.
At my work, we have several 10HP blowers that run 24x7. The 3450RPM blower motor has IIRC a 10" dual belt sheave, and the wheel has a 6" adjustable sheave. The blower motor current draw is ever so slightly lower with a BX belt than with a B belt. The BX is known to save a little energy, and you can actually see the difference with a Fluke meter. I wouldn't call 6" "very small", but BX is thicker than AX...
Anyway, we wear through solid belts in 3-4 months. I've seen BX interrupted belts last as long as a year (both with top shelf brand like Goodyear or Browning matched pairs of belts). The BX belts run cooler (as you'd expect with a link belt as well), which explains why they last longer.
In 5 years of non-stop service, the only cast iron sheaves we've worn out were ones that came from refurbished equipment (with an unknown amount of prior service). I haven't seen a sheave wear out in just 5 years.
Yes, aluminum wears faster. Yes, link belts wear out the sheaves faster.
But
if your belts are aligned properly, pulleys last a LONG time, and its not like you're not turning on your drill press, applying a load, and then going away on vacation for months at a time.