Using blocs

Hello,
(Sorry for such a deep question but I did not find where is the response for the moment.)

I have been trying to use the "Blocs" functions but : I did not manage to use it properly :

- After insert a block : is it normal not to be able to update it ? Some update are possible (trim lines for example) and others not (draw parallel line for example).
- What about the layers in a block created by copying to a block ? Will they be the same as the original copied entities ?

I just wanted to draw once a quite complex object, and to import it to get it in 4 différent places of my final project. But as I know : copy/past the object produces the same effect doesn't it ? Am I wrong to use blocks for that ?

-> In one question : what are the "blocs" functionalities made for ?

Thanks if you can help me a little...

If you "edit the active block in a separate window", the changes are visible instantly in the main drawing also. Access that separate window via "Drawings". I had no problems doing any editing there.
But strange interactions depending on the layers conditions happen, which I do not understand myself. See also the recent postings from forum member electrosteam.
The idea of blocks is to keep your drawing file small and nimble, as the data of a blocks content is only written once in the file, even if it is inserted several times. With copy / paste the file gets bloated.
Sorry not to be able to help more.

So many thanks !
I understand better... so blocks are probably not so appropriated to my situation...