If I don't want to update now, I shouldn't have to. My device, my rules.
And this feature encourages bait and switching: free app is no ads and free, and then at update+1 gets malware installed for free on forced update. We've already seen this with optional updates - only now they won't rely on tricking the user. They'll just update.
If you didn't do that, then you really couldn't force the updates to the old versions.
I disagree. This will just encourage app devs to engage in more forced updates, and forced updates are always bad things.
The major case is game clients for multiplayer games where it doesn't make any sense to split your player community into older versions. Games across all platforms work this way so its nice to see a consistent UI for Android.
However, this will encourage the use of forced updates outside of that use case. That sounds like a terrible thing.