SafeHandle vs IntPtr in WinAPIs and CloseHandle in C#

Question

I read many articles about SafeHandle and IDiposable but I still don't understand whether I should use SafeHandle and CloseHandle or not in C#.

MSDN SafeHandle example

IntPtr, SafeHandle and HandleRef - Explained

https://blog.benoitblanchon.fr/safehandle/.

The first source is similar to my question but however it doesn't answer my question.

Let's say I have the following 3 different examples that I got from Internet:

// Example 1
byte[] temp = new byte[IntPtr.Size];
fixed (byte* p = temp)
{
    IntPtr SectionHandle = new IntPtr(p);
    LARGE_INTEGER MaximumSize = new LARGE_INTEGER();
    MaximumSize.LowPart = pNTHeader->OptionalHeader.SizeOfImage;
    status = NtCreateSection(
        SectionHandle,
        SectionAccess.SECTION_MAP_EXECUTE | SectionAccess.SECTION_MAP_READ | SectionAccess.SECTION_MAP_WRITE,
        IntPtr.Zero,
        ref MaximumSize,
        MemoryProtectionConstants.PAGE_EXECUTE_READWRITE,
        AllocationTypes.SEC_COMMIT,
        IntPtr.Zero);
}

// Example 2
IntPtr hFile = CreateFile(
    path, 
    GenericRights.GENERIC_READ, 
    FileFlags.FILE_SHARE_DELETE | FileFlags.FILE_SHARE_READ | FileFlags.FILE_SHARE_WRITE, 
    IntPtr.Zero, 
    FileCreationFlags.OPEN_EXISTING, 
    FileFlags.FILE_ATTRIBUTE_NORMAL, 
    IntPtr.Zero);

if (hFile == INVALID_HANDLE_VALUE)
    return false;

// Example 3
IntPtr hMap = CreateFileMapping(
    hFile, 
    IntPtr.Zero, 
    MemoryProtectionConstants.PAGE_READONLY, 
    0, 
    0, 
    IntPtr.Zero);

if (hMap == IntPtr.Zero)
    return false;

The examples are Windows APIs, so they are unmanaged. What I don't get is:

1) Should the all 3 examples use SafeHandle over IntPtr because they are unmanaged and if one of them shouldn't, why?

2) I find CloseHandle for a good practice in C/C++ but in C# I don't know if the Garbage Collector closes the handle automatically in the end? Should CloseHandle be used in the above examples and why?

3) The first example uses an unmanaged byte* to allocate memory on the heap. Can this procedure be done by not using unmanaged pointer? The code below is my guess, what do you think about it?

IntPtr SectionHandle = Marshal.AllocateHGlobal(sizeof(int));
... code ...
Marshal.FreeHGlobal(SectionHandle);

Edit: Posting the code I edited:

[SecurityCritical]
public sealed class SafeHandleBuffer : SafeBuffer
{
    public SafeHandleBuffer()
        : base(true)
    {
        handle = Marshal.AllocHGlobal(IntPtr.Size);
    }

    public int GetValue() =>
        Marshal.ReadInt32(handle);

    [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
    protected override bool ReleaseHandle()
    {
        Marshal.FreeHGlobal(handle);
        return true;
    }
}

public sealed class SafeHandleToken : SafeHandleZeroOrMinusOneIsInvalid
{
    private SafeHandleToken()
        : base(true)
    {
    }

    [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
    protected override bool ReleaseHandle() => 
        CloseHandle(handle);
}

// Including the IDisposable implementation in the class where the next example calls are found
private SafeHandleToken _fileHandle, _mappingHandle;
private SafeHandleBuffer _sectionHandle;

public void Dispose()
{
    Dispose(true);
    GC.SuppressFinalize(this);
}

[SecurityPermission(SecurityAction.Demand, UnmanagedCode = true)]
protected virtual void Dispose(bool disposing)
{
    if (_fileHandle != null && !_fileHandle.IsInvalid)
    {
        _fileHandle.Dispose();
    }

    if (_mappingHandle != null && !_mappingHandle.IsInvalid)
    {
        _mappingHandle.Dispose();
    }

    if (_sectionHandle != null && !_sectionHandle.IsInvalid)
    {
        _sectionHandle.Dispose();
    }
}

// Example 1
SafeHandleBuffer tempHandle = new SafeHandleBuffer();
LARGE_INTEGER MaximumSize = new LARGE_INTEGER();
MaximumSize.LowPart = pNTHeader->OptionalHeader.SizeOfImage;
status = NtCreateSection(
    tempHandle,
    SectionAccess.SECTION_MAP_EXECUTE | SectionAccess.SECTION_MAP_READ | SectionAccess.SECTION_MAP_WRITE,
    IntPtr.Zero,
    ref MaximumSize,
    MemoryProtectionConstants.PAGE_EXECUTE_READWRITE,
    AllocationTypes.SEC_COMMIT,
    IntPtr.Zero);

// Example 2
SafeHandleToken tempHandle = CreateFile(
    path,
    GenericRights.GENERIC_READ,
    FileShare.ReadWrite | FileShare.Delete,
    IntPtr.Zero,
    FileMode.Open,
    FileAttributes.Normal,
    IntPtr.Zero);

Thread.Sleep(500);
_fileHandle = tempHandle;

if (_fileHandle.IsInvalid)
    throw new Win32Exception(Marshal.GetLastWin32Error());

// Example 3
tempHandle = CreateFileMapping(
    _fileHandle,
    IntPtr.Zero,
    (uint)MemoryProtectionConstants.PAGE_READONLY | (uint)AllocationTypes.SEC_IMAGE,
    0,
    0,
    IntPtr.Zero);

Thread.Sleep(500);
_mappingHandle = tempHandle;

if (_mappingHandle.IsInvalid)
    throw new Win32Exception(Marshal.GetLastWin32Error());

Do you think I did everything alright? Should SafeHandle be used on every Windows API like GetModuleHandle, GetProcAddress, MapViewOfFile and some more I don't remember right now. Some of them are returning LPVOID.