Yes, it would be helpful for a lot of cases like title screens and locating metatiles. From the games I've tested, most don't really have compression, but yeah, it wouldn't be useful for some games.
About using metatile tables that's part of what I asked helped to do on the super pitfall map editor. There's isn't a general use map editor that does that, is there? My idea is that the editor can be flexible enough to be compatible with more games later.