Does encrypting an Android device add any real security benefit over a key-lock? Would encrypting my Android device make my data any safer in case of theft?

It seems to me that since the encryption key necessarily is identical to the PIN code or password used for the key-lock, gaining access to the phone data simply relies on recovering the PIN code or password or somehow bypassing the lock mechanism. And this applies regardless of whether encryption has been applied or not:


Without encryption an attacker must unlock the device with the PIN code or password to access any data
With encryption an attacker must decrypt the device with the same PIN code or password to access any data


So encrypting the device or not does not seem to actually matter!? In either case the thief must recover the PIN code or password (or bypass the lock mechanism) to access the phone.

Are there any scenarios when encryption actually provides added protection beyond the key-lock, considering the above?

Please consider the case of a factory default Android 4.4 KitKat device, that is not rooted, and that does not have developer options enabled.

Note that I am not aiming to protect my data against people and organizations with extensive capabilities, like forensic and massive code-breaking tools. I'm simply wondering whether enabling encryption actually will really yield any added security against your average hobby hacker with skills in rooting etc.
Decrypting the device and bypassing the lock mechanism are completely different things. The request for the PIN code/password in the standard lock screen occurs AFTER the device has booted. It is possible bypass it by gaining indirect access to the already available data. And bypassing the lockscreen password is relatively easy.
With encryption enabled, it occurs BEFORE the boot and there is NO data that can be obtained without getting the actual key. There is no bypass there, except extracting the key from you by physical force... (An obvious assumption here is that the actual encryption mechanism/software does not have obvious bugs, but this assumtion undermines ANY discussion on security whatsoever, so I'm not taking it into account).
Your phone may have an external SD Card with lots of data on it (like mine). Encryption will protect it if the phone is lost, since ejecting it and trying to mount it elsewhere will fail. That's not a "forensic-level" attack.