There is one advantage of aglie, we can get the clients to test the system when the parts built during the sprint, rather waiting the testing stage. If the bugs can be found as near as the time of its creation, that would be the best. The developer should be the best memory about the buggy parts. That is better to wait for the testing stage. Maybe a month, we need to understand the bug report and "search" our memory, how those parts works, how come the bug is created. That is not good!
Thus, getting bugs fixed should be carried as easily as possible!