Poles

[Oracle]

On the other hand they are an absolute nuisance when you need to navigate, eat, or kit faff. And I only really find mine helpful during non runnable climbs, they don't help much descending and are just dead weight on the flat.
The bottom line though is that people might be forced to give up long races earlier than they otherwise would - whether that's 65 instead of 70 or whatever, and that's a shame.

Seconded, on the last point.

I think Most of the field use them on such as TMB
And ultra trail runners have found ways to dismantle them into a quiver so not the incumbrance they might seem. I disagree on descents, that is where they help.