I generally don't use "bulk" parts per se. I make a real part and use it as a bulk item. Why? Well, with a real part I can constrain it CS to CS, and can repeat the part in the model tree so if I want to swap out one instance of a bulk part with another I can. For instance, things like oil or grease, etc. You can make a family table of the bulk part(s) and change viscosity, etc. For weld filler metal, you can create a fam tab of different materials, and easily put multiple filler metals in the assembly and in the notes say you can use one or the other and both will show in the BOM. Yes, I know you can make a fam tab of bulk parts too, but I like being able to pattern or repeat the instances like you can with a constraint. Plus, as mentioned, if you want to point a leade to it what you can do is do a copy geom and copy a surface from one of the parts. This will allow you to put a leader where you want it, say, for sealant at the sealing surfaces of 2 parts.
