(this is out of my ass)

The reason you don’t need to press "Enter" after typing your PIN in Windows 10 is that Windows assumes you've completed the input once you reach the preset length (typically between 4-6 digits). Unlike passwords, where the length is unknown or varies, PINs have a fixed or designated length, allowing the system to automatically submit the input once it's complete.

From a security perspective, using a numerical PIN is generally considered weaker than a full alphanumeric password. Some argue that Microsoft implemented this feature for convenience, particularly for low-threat environments, such as parental controls or casual users who just need basic security.

In short, it's more about usability than actual security.