This service store the reconstruction to a file on the Parrot S.L.A.M.dunk.
The procedure to record a point cloud is described here: Can i record Point of Cloud?
These services are useful to restart the various services you can subscribe to.
In the past, after changing the camera resolutions with dynamic_reconfigure, one had to restart the capture manually.
That is why this services existed.
Now this is done automatically so there is probably little reasons to call them.