Using the app Streetcomplete, it's really easy to correct OSM data like street numbers and opening times around you as you walk.

I have been working on adding all street numbers for a small town of 40,000 people. Two years into this project, I am still little more than halfway done. Adding a handful of street numbers with StreetComplete might be "easy", but it is incredibly labor-intensive to add street numbers in an amount that makes OSM actually useful for navigation purposes. Google only managed to get their house numbers by forcing the world to do the work through ReCAPTCHA or by buying the rights to various preexisting databases.

I wonder if OSMand could take advantage of having a few street numbers. Right now, in the "address search" mode, if the number you're looking for doesn't exist, you're out of luck. But theoretically it could accept any street number, and if a street even has a few numbers in place (I often find random street numbers probably entered by residents or shopowners) it could at least tell you "it's somewhere between here and there". Even that would be vastly more useful.

Then mapped crusaders like yourself could first focus on adding numbers in the middle of streets, and then gradually, in binary search fashion, continuing to halve unnumbered street sections.

One of the biggest challenges with mapping house numbers is simply getting to that street to begin with. It takes a volunteer making an effort to go to various parts of town that he/she doedn't normally go to, since most neighbourhoods don't have their own local mappers interested in adding house numbers.

Once someone has made that effort, then it isn't too much extra effort to do all the house numbers. So, no need to restrict oneself to the middle of the range.

OSMAnd's address search feature already allows you to choose from among the house numbers that do exist for a street, even if the whole street isn't mapped, so it is often easy to navigate to the general ballpark of your destination.

If you can make it a as addicting as pokémon go, it might work. It looks like they are trying since you get some points for "playing"