Aways are primarily for auditioning at a specific program you realllllly like and/or getting an additional LOR if your program can't supply one.
Strong application? Don't waste your time.
Meh application, or coming from an institution without its own ophtho program? Consider.
Aways take a lot of time and money and effort for little payoff. Plus, because of the timing, you're usually doing aways after SF Match opens and after programs have already started screening applications, so scoring an interview through an away along is a long shot. It's also not very likely that you'll get an LOR through your away.