How Much Good Practice Is To User Asp:SqlDataSource

I know that <asp:SqlDataSource> is fast, but is it a good practice to use this. The sqldatasource is right there in the aspx page and the SQL for sqldatasource is also right there.
Does that not break the 3 tier model, as normally we call a database layer and we have all the SQL's there. 
In one of the code in saw the following. I don't know if it is a good practice to do something like this.

 <asp:DropDownList  ID="CountryDropDownList" runat="server" DataSourceID="SqlDataSource2"     DataTextField="PickListLabel" DataValueField="PickListValue" OnDataBound="hidePanel">
                                                    </asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:webrepos %>"
                                                        SelectCommand="SELECT [PickListLabel], [PicklistValue] FROM [PickList_Values] WHERE (([ObjectName] = @ObjectName) AND ([FieldName] = @FieldName)) ORDER BY [AbbrCode]">
                                                        <SelectParameters>
                                                            <asp:Parameter DefaultValue="Account" Name="ObjectName" Type="String" />
                                                            <asp:Parameter DefaultValue="Country__c" Name="FieldName" Type="String" />
                                                        </SelectParameters>
                                                    </asp:SqlDataSource>