18 January 2019
Rahul has given a good explanation of the benefit of a conformal mesh.
If the faces on the two parts are the exact same cylinder, but just have different extents, you can pick the two bodies in the DesignModeler outline and RMB to Form New Part. This puts the two bodies in a Multibody Part and then in the mesher, you will get a conformal mesh. There will only be one set of nodes on the common cylindrical face, and the elements on each side will share them. This is called Shared Topology and means you no longer need Bonded Contact.
This could be a good route, but you will probably end up with a Tet element mesh. If you do a lot of geometry preparation, splitting each body so there is exactly the same face on each part touching, you can apply a Match mesh control and potentially get a Hex element mesh.