Every time there is a new version of the phptoshop the creative clowd is becoming the most annoying thing on the plannet - deletes your existing version and forces you to wait and update the photoshop. Few times already I am getting frustrated customer as I try to show them some work and can't open photoshop as it disapears for update that takes up to an good hour befor can be used again.
If you don't want automatic updating, just turn it off. In the CC desktop app. Then you can update when it suits you or not at all. You also get to choose whether to delete the old version - I would never do that.
Yes, you're right. For "minor" updates you can't keep the old version because it lives in the same place. This is not a good situation. But I would always keep two functioning versions of any app and update only one at a time.