Here is the answer guys on your questions why i need to do that. Watch this Blender tutorial and you will understand why extruding single vertices can be useful. https://www.youtube.com/watch?v=MdAR-O_DwSs
You can make a whole model by only extruding the vertices,connecting them and then fill them with faces in one click like he does it at 6.52 on tutorial. And this is just one example but i remeber when i was modelling this car in Blender -https://www.youtube.com/watch?v=dhESzRJgv0Y i was using it a lot in different places of the mesh
So basically extruding single vertices can be very useful for tracing the object. For example when you use blueprints you trace blueprint all the way around and once you happy you just fill the holes with faces
But it seems like Maya allows extruding vertices but its completely useless because you cannot fill them with faces or even connect two vertices together