Even in a limited form its still something new that we've never had before. For people that lived alone there was simply no other option but to be nearby to hear the beep. The whole point of Alexa is to have something that can take over some of the things another human would normally have helped you with.
Perfect is the enemy of good.
It's kind of like saying that using a rotary phone UI on your smartphone would have been okay, because we've managed with it just fine for a long time back when we had rotary phones.