Though I would propose that in the vast majority of applications, the amount you're going to need to do graph-like operations is significantly outweighed by the

Though I would propose that in the vast majority of applications, the amount you're going to need to do graph-like operations is significantly outweighed by the amount you're going to need to do regular relational-type operations. Being able to do them "well enough" without adding yet another moving part to your system (one which holds data that probably needs to be synchronized with other data stores) is extremely valuable.