Dim myarray(5) As Integer
Dim myint As Integer

For Each myint In myarray   ' <-- compile error here
    ...
Next

I mean, the obvious answer is: Because the spec (Section 5.4.2.4) say so.

So, the question is: Why does the spec require this? When iterating over a collection of objects, I can use Object or the concrete type as the iterator variable. It would seem natural to use a variable of type Integer to iterate over an array of integers.

Completely unrelated fun fact: I've been using VBA for more than 30 years now, and only now (while reading the spec) I discovered that the following code is legal. Not that I would ever do this...

Dim row, col

For row = 0 To 5
For col = 0 To 5
    Debug.Print row, col
Next col, row