OK, gotcha.
The challenge is that some helmets (especially MTB ones) seem to clash with the ends of the arms, and when worn (correctly) over the straps can create a levering action on the straps as well as pressure points under the edge of the helmet. I get a bit of this with my MTB helmet and glasses, but it doesn’t tend to bother me too much, but it was nice to be able to shorten the arms right off on the Jawbreakers to keep them well out of the way.
For example, here’s my MTB helmet (Hardnutz) combined with my Tifosi Dolomites and you can see where the ends of the arms get very, very close to the helmet webbing:
For me, wide arms are far less of an issue than arm length. You can see that the Jawbreakers can be set with far shorter arms and these stay away from the helmet and are generally comfier to wear:
Interestingly, the wider arms don’t seem to cause any discomfort with this helmet – there’s actually a recess that they fit into, so they don’t actually touch at the front.
(In truth, this is the first time these glasses have been worn with this helmet – I just wanted to show the difference between the two)