What is the difference between Product Assembly & Component Assembly In Catia?
In Assembly Environment there are two options insert component or product so, what does it actually mean?
3 Answer

It means that you can assable products in yout product. Some times it is easier to assamble some parts to a product, and import them as a product in your general product.
So you can reduce your number of constrains, etc

Component does not have file i.e. we can add the parts into components and by copying we can use number of times within a CATProduct, without generating lots of file.

After lots of searches, I got these answers well explained. Hope you understand it
Component allows you to group things within in a CATProduct assembly
When you create a sub assembly using component you can use within an assembly file you can’t use it in another assembly. But when you create a sub-assembly using Product you can use in another file and even you can save it as a separate product file but you can’t save as a separate assembly if you use component option.
A product can be saved in a separate file and can be opened in a separate window while a component cannot do both