Necessity of being assemble boolean command

[AFROUZ.E]

As you know, a body has a polarity (+ or -), and it's possible to create a body with + polarity and remove it form the partbody by remove boolean command or to create a - minus body and assemble it to the partbody by assemble boolean command. So, which way is correct or better than the other?
And what's the necessity of being the assemble command in CATIA, when we are able to use just add or remove command along with + body?

 

[MrCATIA]

I agree with you; it seems the Assembly operation is not absolutely required. But it does come in handy when you decide to take an existing Pocket feature and insert it into a new body without having to replace the Pocket with a Pad.

I guess this is another command that adds flexibility to CATIA V5.

Which is correct or better? I don't think either operation is wrong. But the ADD and REMOVE operations are more descriptive and obvious when reviewing the tree structure. The ASSEMBLE operation requires a little more investigating to understand, so is probably not used as much.