Regarding public trips: One perhaps fringe feature I liked about them was to look for hosts in an entire region. Outside of dedicated city trips I’d regularly need a host in roughly this distance but not in that specific place.
And then there was that one time (probably not something I’m ever going to need again, but who knows!) I’ve been interrailing, had some days without a concrete plan and tried looking for a host anywhere in Italy. Found some places I’d never have visited otherwise!