Crap, I forgot we were on a thread about smart watches. I wouldn’t know how it works on one, since I don’t own any.

But turk by turn works as good as it can for any public transport service. It tells me when and where I need to change. How long the change is and things like that. I assume a lot of it depends on the data provided by the transport company

Your last sentence is the only valid complication, all the other issues exist just the same on phones and Google has already solved them in their existing apps.