ByVal, ByRef. The real use, beyond the lesson. VBScript

...but is also valid for all members of VB family.

Dim varA, strMsg 

varA = Int(InputBox ("Input the initial value:"))
strMsg ="'varA' initial: " & varA & Chr(13) & Chr(10)

varA = TransAVal(varA) 'varA ia valoarea functiei / varA it takes the function's value
strMsg = strMsg & "'varA' after TransAVal: " & varA & Chr(13) & Chr(10)

varA = TransARef(varA) 'varA ia valoarea functiei / varA it takes the function's value
strMsg = strMsg & "'varA' after TransARef: " & varA & Chr(13) & Chr(10)

ValA varA 'varA isi pastreaza valoarea / varA keeps its value
strMsg = strMsg & "'varA' after ValA: " & varA & Chr(13) & Chr(10)

RefA varA 'varA ia valoarea finala a parametrului din functia RefA / varA it takes the final value of the RefA function parameter
strMsg = strMsg & "'varA' after RefA: " & varA 
WScript.Echo strMsg

Function TransARef(ByRef x)
TransARef = x + 1
End Function

Function TransAVal(ByVal x) 
TransAVal = x + 1
End Function

Sub ValA(ByVal x)
x = x + 1
End Sub

Sub RefA(ByRef x)
x = x + 1
End Sub

Conclusion:
ByRef and BvVal have no influence if you return the function to assign it to a value. This is the most common situation.