You have no idea what you're talking about, and neither do any of the other people that mentioned this. Also, everyone is a day or more late on this. Taking a picture of the rock for reference is key not for just modeling but for texturing. It's very commonplace in video games for people to take high definition high quality pictures of things like walls of various materials concrete brick etc floors path ways, rocks like this, wood etc. Just go look online for high definition textures of things and you'll see what I mean.
What are you talking about? Rocks and other elements in game are critical to creating a good looking environment. Software exists for these sorts of things for the sole purpose of just PLACING these environmental elements into a game world that costs a ton of money. Here's an example:
http://www.speedtree.com/ this software has won awards and is used in not only games but high production Hollywood movies like the new Jurassic Park movie and Avatar. These things are important, companies spend thousands of dollars to get high production because it makes for a realistic end product. I don't know what you mean by "hiding behind", that's not the sole purpose of the rocks, also that's not what will be happening in the final game anyways.
Artists use reference to create realistic looking drawings. It's the only way to get good at drawing, by trying to draw real things. Creating realistic rocks that fit with a certain climate and surrounding area is key to creating a convincing environment. You wouldn't put a pine tree in a desert, would you? Also, the team that did this is the same team that put together that video of them going around into caves, seeing those different animals, hiking up mountains, fishing, watching explosions and other similar things from different weaponry all for research and reference. Look at developer commentary for various games some will talk about the research and things they for various aspects of a game.
I'm glad to see the Japanese users on the JP Tweet take it as it should have been and actually responded with a lot of really cool areas with cool rocks it was really awesome to see people enjoying the idea. The translation for the Tweet made it seem weird but honestly it wasn't hard to understand what people were saying.
This is another case of people looking at something like this and saying that somehow XV marketing or otherwise is doing bad (I'm not talking about you I'm talking about others I've seen) because they post something like this and people think it's stupid because they don't understand the point behind it. Meanwhile, Japan is just like "oh that's neat" and maybe engage a little... like it shouldn't went down. Instead, more than 24 hours later NeoGAF slowpokes find it and make a thread all saying the same joke over and over again belittling the development team and their hard work over something that really isn't that funny to begin with.
Don't take this message the wrong way by the way, this is more directed at other people I've seen and not at all something personal against you.