Why do many domestic mobile game nicknames have a maximum limit of 7 characters?

Adding a length limit to the name will help UI developers avoid truncate/overflow issues with long ID display. (You must know that when making UI, the placeholder commonly used by many people is "the nickname can be up to seven characters")

As for why it is seven characters, maybe it is to make it easier to read poetry, right?

Let’s see what happens if you don’t limit the length of your name! ! !

For example:

This:

Or:

Also:

Even:

Now, look me in the eyes and tell me why many game nicknames are limited to seven characters?