If a dynamic kit has been created, for example by clicking, does this mean that Angular when re-clicked, it will not be re-created, and return existing in the state in which it was at last time use?
Destroy of course, there will he forever keep it. Save the component in the parent, or those "dynamic" components generated by the router, using the strategy of reusing.
Weighs whether in tamo case, the project less?
No. The weight of the project code descriptions of your templates and classes. Read on classes and constructor functions in js.
What's the different from ngif?
The dynamic component you can create not showing him, to give him any context and the injector. You cannot pass input parameters (well, by default it is impossible, in General, you can directly initialize a field, or use libraries).
Tell me how to create a sheet with dynamic components and to manage them? Hide, show, destroy, or receive data from one?
It is not necessary to obtain component of any data. Exactly the opposite, the component must retrieve data for display from any of their sources (ie from the injector).