I don’t understand, two directives are called differently, but do they have any differences?

Question

1C

it is about &AtClientAtServer and &AtClientAtServerWithoutContext

Answer 1

1. How a server call works in 1C
2. Optimization of client-server interaction in 1C

Answer 2

Well, no, no context!
In the first case, the code can be executed in the context of the form, but not in the second.