This was discussed upthread, but it's worth a reminder that most US-Asia fares allow routing via the Hopper. For example, it can be routed on
this YYZ-OSA J fare (and there's no $500 Hopper surcharge). Thanks to
Quail for helping book one for me.
A useful corollary is that there seems to be extra married segment availability on the <CONUS>-HNL leg of <CONUS>-HNL-GUM-<Japan> that isn't available separately. Matrix / ExpertFlyer are terrible at displaying it, but here's an example for P availability on DEN-HNL:
I haven't seen any examples where this added availability on the Hopper itself, though.