I also just gave it a go. I live in Amsterdam where biking is pretty much the dominant mode, and it wasn't great. I told it to take me to a place in the north of the city (over a river), and it gave me directions over a bridge which is about a 14km trip rather than via the free ferry which makes it more like 4km. It also oddly doesn't optimise to the route I usually take (for the segment that makes sense) which is both shorter and quieter. Perhaps it tries to minimise corners, but on this route it doesn't make sense to.

OSMand both has the "shortcut" and knows about the ferry.

For me ideal bike routing is like car routing (main road uses shortest distances and has fever intersections - which is safer) but uses bike paths when it is shorter option.

Unfortunately most bike routing apps will always prefer bike path even if it is just 100m along the main road where you need to go of the road and then return.

For the bike use-case OsmAnd might be better, as other replies in this HN entry suggest.