Where to create child control objects - property accessors (get) or CreateChildControls

I know the .NET system is designed for custom controls to create their child control methods in the CreateChildControls method, and then call EnsureChildControls() before accessing any of their properties, like the following example:

Protected Overrides Sub CreateChildControls()
            _txtSearch = New TextBox()
            Me.Controls.Add(_txtSearch)
        End Sub

        Public Property Text As String
            Get
                EnsureChildControls()
                Return _txtSearch.Text
            End Get
            Set(ByVal value As String)
                EnsureChildControls()
                _txtSearch.Text = value
            End Set
        End Property

I don't see why this is necessary.  Couldn't we just use a property accessor model, create controls there, and add them to the controls collection in CreateChildControls?  That would eliminate the need for using/remembering to call EnsureChildControls() on property access!  FYI, I have tested this method and it works fine.

Private _txtSearch As TextBox = Nothing
        Private ReadOnly Property txtSearch As TextBox
            Get
                If _txtSearch Is Nothing Then
                    _txtSearch = New TextBox()
                End If

                Return _txtSearch
            End Get
        End Property

        Protected Overrides Sub CreateChildControls()
            Me.Controls.Add(txtSearch)
        End Sub

Is there some reason I'm missing to use the EnsureChildControls model instead of the property accessor model?