What’s the point of deactivating Num Lock on login screens?

Many login screens automatically deactivate the Num Lock key on the keyboard before the user can enter their password. This is extremely frustrating for the user as they involuntarily type their password wrong multiple times before realising the Num Lock key is off.

Several undesirable side effects include:

• Missing the password involuntarily 3 times, thereby locking the system,
• Having a timeout after each missed password attempt, sometimes up to several minutes,
• Frustration when one repeatedly forgets to activate the Num Lock key.

Moreover, I don't see what the reason for this would be from a security viewpoint. It does not enhance the quality of the password nor does it ward off any potential attacker.

So why are very widespread systems still using this extremely frustrating methodology?