The update can be analyzed to see what was changed, even if we only have the binary executable. If we know that an app contains intentional bugs, just looking at where the update made changes could eliminate a lot of looking & find the bugs even faster! There are many automated tools that can do this too, eg. Fuzzing. The updates can also hint us where the previous bug was and what to look out for in the future.

So, nope. Introducing security bugs and backdoors just makes it insecure for everyone.