Why does RC make new models (1Ds)?

I’m trying to understand what I’m looking at here in the 1Ds viewport:

So there are my images and control points, I think those are pretty straight forward.

Small Components: why do these exist? Can I group/merge them? My current project has (6) "Small Components, with “less than 35 cameras”, what does that say about the data I captured?

Main Component: this is the real meat & potatoes of my question right here: I have (8) “models” (and that’s after I’ve deleted a few during all this) and when I run certain commands like close holes, simplify, etc. it creates another new “model” in this space…why? And why doe I then lose classes when I get this new model? I guess I’m trying to understand exactly what these “models” are and what elements makes a “model”?