Rigs and models depend on residing within a single assembly of a particular name. Because they are assemblies, no two names can be the same. Ergo, only one asset may be published from a scene at any given time.
When and why would you want to publish multiple assets from one scene?
Multiple resolutions of one model. Such as a proxy modeled after a high-resolution model. They both share a tight connection where if one changes, so does the other. Developing these together, publishing these together makes sense in some cases.
Small project, small rigs. When a simulation rig depends on an animation rig, they both share a tight connection and developing them together becomes favourable. In these cases, publishing them together makes sense.
Description
Rigs and models depend on residing within a single assembly of a particular name. Because they are assemblies, no two names can be the same. Ergo, only one asset may be published from a scene at any given time.
When and why would you want to publish multiple assets from one scene?