Php framework-ThinkPHP's HTML template file uses PHP super global variables. Why is this format used?

The second line of {code...} is for the tutorial. The first line is for my own test. The tutorial does not. The two outputs are the same. Why are 2nd types used in the tutorial? Is it for security reasons or other factors? Thank you.

{$ _ SERVER ["REQUEST_URI"]}
{$ Think. SERVER. REQUEST_URI}

The second line is for the tutorial. The first line is for my own test.

The two outputs are the same. Why are 2nd output types used in the tutorial?

Is it for security reasons or other factors?

Thank you.

Reply content:

{$ _ SERVER ["REQUEST_URI"]}
{$ Think. SERVER. REQUEST_URI}

The second line is for the tutorial. The first line is for my own test.

The two outputs are the same. Why are 2nd output types used in the tutorial?

Is it for security reasons or other factors?

Thank you.

For example, {$ _ SERVER ["REQUEST_URI"]} directly accesses the server variable {$ Think. SERVER. REQUEST_URI} is encapsulated by tp. Of course, the second type will not be described in the tutorial. There are too many tp chicken ribs.

It seems that TP is not very useful in doing so. It is more efficient to use native, saving compilation, and the variables after compilation are the same.