is unsafe code really that unavoidable?

var array = new [] { 1, 2, 3, 4, 5 }   // <-- Array
                  // ---^^^^^^^---     // <-- A "span" of elements: start index being 1, including 3 elements.
var span = array.AsSpan().Slice(1, 3); // <-- A span that represents the above

var array = new [] { 1, 2, 3, 4, 5 }   // <-- Array
                  // ---^^^^^^^---     // <-- A "span" of elements: start index being 1, including 3 elements.
var span = array.AsSpan().Slice(1, 3); // <-- A span that represents the above

void SomeThing(int* a)
{
}

void SomeThing(PointerLike<int> a)
{
}

void SomeThing(int* a)
{
}

void SomeThing(PointerLike<int> a)
{
}