Hi!
"Maya likes to create groups with certain commands(extract), regardless of whether history is turned on or off"
- Only if needed.
Ok let's take these commands as examples.
a) Extract
1. If you don't use separate, no new names or groups will be created.
2. If you use separate, then new object(s) will be created and this means new names.
So to make sure you can keep track of the process and for a good overview, the NEW separated objects will be grouped under one main group with the original object name, so the group still consists of all original components.
Seems logical to me.
(Keep in mint that this process can easily create hundreds or thousands of objects, which are easier to handle if grouped)
b) Combine
1. With history "off", no groups will be created, you just get a new name which is based on the original name.
2. With history "on", the original states have to be preserved, so there is no other way than to keep the original objects and create a new one.
I can't see anything unnecessary created, for both commands.
Also as mentioned before if you want or need a different behavior for some reason, you can create customized commands that do exactly what you want.