OpenStreetMap is incredibly important. So many map applications and project composed from open-data is dependent on OSM (yes, european alternatives to map applications heavily depend on open-data of OpenStreetMap which is actually a database of geographic information, not only the map layer you often see).
I posted awhile ago about Organic Maps which also allows you to edit certain information. But StreetComplete is more fun :)
Microsoft and Apple use OpenStreetMap to an extent. Even TomTom uses it and, probably, Google. The better we make it, though, the less value adds other players can claim and no one can monopolize good street map data.
Did streetcomplete.app get a hug of death? It's down right now. Anyway, sounds like a cool idea to map it.
Anyway, looks like osmand app has a plug in for it too, neat.
For hiking and cycling it is absolutely supreme to google in every way. Google will often just send you a "car-path" by foot or bike, while OSM will try to steer you to smaller, slower roads/paths (and way more of those are mapped on OSM then on google).
The main issue on OSM for me is the lacking up-to-date business information... If OSM shows shops on maps: don't rely on it. It would be very interesting if the business/reviews/pictures etc part of google maps could somehow make it (open source version) to OSM.
Yes, you have to download the local area. Processing happens on your phone.
Organic Maps is a bit smoother to get started with but I'm very happy with OSM& now I have it set up as I want and was also glad to have it when renting a boat on vacation. If you're new, try Organic Maps first.
I've been using StreetComplete for over a year now, on and off (currently globally ranked #1555 & #132 in my country 🙂) and it's so easy to use.
It's a great feeling to add a local shop / cafe's opening times and then see that in OSM.
Similarly my house (and close neighbours) didn't appear in the map of our local village, so I worked out how to edit in the OSM website and our houses, inc. house numbers are now there so deliveries are now more reliable.
Just a little bit by a few people and it makes the world a better place.