Volatile vs VolatileRead/Write?

I can't find any example of VolatileRead/write (try...) but still:

When should I use volatile vs VolatileRead?

AFAIK the whole purpose of volatile is to create half fences so:

• For a READ operation, reads/writes (on other threads) which comes AFTER the current operation , won't pass before the fence. hence - we read the latest value.

Question #1

So why do I need the volatileRead? it seems that volatile already do the work.

Plus - in C# all writes are volatile (unlike say in Java), regardless of whether you write to a volatile or a non-volatile field - and so I ask: Why do I need the volatileWrite?

Question #2

This is the implementation for VolatileRead :

[MethodImpl(MethodImplOptions.NoInlining)]public static int VolatileRead(ref int address){    int num = address;    MemoryBarrier();    return num;}

Why the line int num = address; is there? they already have the address argument which is clearly holding the value.