well no, you still need to look at what people have claimed - other than just looking at the .claim markers
The claim marker will mark one block on the map - it won't show how big an area someone wants to claim. So the advantage of people posting a screen shot of the map with their land area circled, means you can see how big an area the person wants to claim - you can't tell that from the .claim marker alone. There should be more than enough land generated now for everyone to build far away from anyone else, but when claims start getting close, you need to know exactly where the reserved areas are, so you don't encroach.
Plus the .claim marker will only allow you one claim spot. The idea of the .claim marker is to mark out a point of undeveveloped land you want to stake a claim to.... and once you've built something there, you put a warp point to it. Several of us have more than 1 reserved/taken area on the map... so again, just looking at the .claim markers won't tell you all the spots on the map that are reserved by players.