This isn't (or ever really directly indented to be) any kind of generic mapping service, or a map-driven interface for Wikipedia. Wikimapia (and other services!) provide interfaces for that. This is the first draft of a tile service that may be integrated into different spots throughout the project -- not an alternative to those kinds of things. It's basically just because Wikipedia can't use a tile service like the default OSM mapnik server without totally crashing it, so they need to build their own tile rendering pipeline, etc.