When doesn't it work? I land on the beach. I meet Shadowheart. I fight devourers, Tutorial teaches about End Day. If I don't End Day right then, I never trigger Gale's Mirror Image dialogue. I barely did anything, might be full health with full spell slots, but game makes me End Day or miss dialogue.
I never end my day there and I always get the mirror image cutscene. I usually rest once after completing the overgrown ruins and once after the grove fight + underground passage + harpies and always get both the "go to hell" and "mirror image" cutscenes as long as I don't talk to Nettie, which would trigger Raphael and override the mirror image scene.
While I do agree that some convos that currently only occur at end of day could happen along the way (e.g. Wyll's convo about seeing Tav fight at the grove gate) I believe that the "go to hell" and the "mirror image" scenes only make sense at the end of the first and second day.
I also don't like the idea of going back to camp every time someone has something to say. It's already bad enough having to go back there at the end of the day. It would be nice if short rests could be turned into something more than a quick way to heal/reset skills and could give you the chance to catch up with companion convos you triggered while adventuring.
