When I'm planning a route on roads I'm not familiar with I need to check various junctions / roads on street view.
At the moment this means I build the route in strava, then have to cross-reference with Google Maps (or whatever your favourite street level photo source is). This is crucial for ensuring it's going to be a fun ride as roads vary dramatically in busyness where I live, and aren't necessarily indicated by size of road. Unfortunately this process is pretty tedious/tricky.
I'd love to be able to drop a few points down on the map and see what the road/junction looks like.