I really like the idea of a camera mod. Create an image of what you see and put it on a wall later. This could be used for various creative things. The picture taking itself works fine but is oddly done with a command rather than an item or something.
Sadly, due to the limitations of Minetest, there are several drawbacks and limitations:
Only b/w images
Objects and players are invisible to the camera
Custom block shapes are not supported. In the photo it either becomes a full block or no block. E.g. plants are not drawn correctly
Picture calculation is slow, it can take several seconds
Making a picture blocks the entire server. So while the picture is calculated, everything else comes to a screeching halt
While the first 3 limitations may be acceptable, the performance problem is the biggest show stopper right now.
This mod clearly tries to put Minetest to its limits and it's definitely worth checking out because it's something very unique. But I don't recommend this mod for actual gameplay or server use. Consider this mod experimental.