Why would I call new without storing the ptr?

Today I was reading though some source code and I encountered this

Pool<C> *pool = accomodate_component<C>();
new(pool->get(id.index())) C(std::forward<Args>(args) ...);

And this line confused me

new(pool->get(id.index())) C(std::forward<Args>(args) ...);

I didn't even think that it was legal C++. As it turns out pool->get(id.index()) returns a size which told me that it could be possible to tell C++ explicitly how much size it should allocate.

I looked it up and yes it is defined that way void* operator new ( std::size_t count );

Now I know that this is legal C++ but what I don't know is its purpose.

Why would I ever call new(size) Foo();. Shouldn't this be a memory leak? And isn't it completely pointless? If I don't have the ptr how I would ever access it?