After a bit of testing, here are my initial thoughts:
Design. I love the navigability of the map, where the features are clear enough to chart my own path. This is essential for commuters on places where Google Maps haven’t covered the public transportation. In contrast, Google Maps is extremely cluttered, filled with too many icons, and names of streets and establishments wouldn’t appear unless zoomed very closely.
Though there are still some room for improvement. First, I suggest using a different color for buildings to create larger color contrast to the roads. Second, add layers for public transport, at least trains or subways, similar to what Organic Maps has implemented. Both would improve navigability even further.
Information. Although the map can search for the location, it needs to have a dropdown box that list possible hits as there are often a lot of establishments and streets with the same names, or with multiple possible names. Like for example, in Google Maps:
I find this necessary for filtering the results, as it’s very rare to have an exact address of a location down to the last detail. This could also resolve one of @videonas’s concerns, where typing in “Nokia” will show a list of locations with that name, and he could then select which one fits his search.
Also, I think this is still too barebones, a map should at least have a way to click on the streets and establishments, and access the rich info provided by the volunteers on those elements. You could also add reviews from 3rd-party sites, essentially picking up where Google failed.
Navigation. This is, as of now, nonexistent. As @mike has stated, an ability to choose the starting point, the destination, and the preferred mode of transportation would be necessary for navigation to work. But it might be too much work in-house, perhaps a partnership with one of the apps using OSM would be more feasible? Where they would provide the routing algorithm, while Mojeek Maps would advertise them, as good routing will encourage more people to download and pay for their app.
Overall, at this phase, I see no use case. Though I would be looking forward for developments and be willing to test those.