The new Purge enhancement has been voted among the Top Ten Ideas at SOLIDWORKS World by the SOLIDWORKS User Community.
I believe people thought that because a command with this name exists in AutoCAD, we need to have it in SOLIDWORKS too, without really considering the differences between a drafting software and an intelligent parametric 3D design tool. At that time I was not a big supporter of this function, because it was not made clear what things should be the subject of purging.
Fast forward to the 2016 release and, as expected, the new Purge command is now part of SOLIDWORKS. I said as expected, because SOLIDWORKS is really, really good at listening to its users and implementing their enhancement requests.
Unfortunately, the way it is implemented now in the 2016 release (SP01) the Purge command can be extremely dangerous, considering that the purged features could be used outside of a part and their absence could create huge errors in huge number of assemblies where the part is used as a component.
Moreover, the destruction is silent and its effect might not be even noticed until the affected assemblies are opened. So a whole team could be affected without even knowing!
For the time being, I suggest being very careful in using the Purge function. It is dangerous for an untrained user.