The PostgreSQL Prepared Statement or Parameterized Statements are always good for specific purpose like: can create Prepared Statement for frequently executing query of a session, It also prevents from SQL Injections.

Prepared Statements are faster for a particular session because It does not require parsing and compiling for each execution. It is only session specific and once a session kill, Prepared Statements automatically destroy.

Here, You can access more on Prepared Statements.

Prepared or Parameterized Statements in Database System

Small demonstration of PostgreSQL Prepared Statement:

Create a table with sample records:

CREATE TABLE tbl_Students 
(
	StudID INTEGER PRIMARY KEY
	,StudName CHARACTER VARYING
	,StudClass CHAR(1)	
);

INSERT INTO tbl_Students 
VALUES (1,'Anvesh','A')
,(2,'Neevan','B'),(3,'Jenny','C')
,(4,'Roy','C'),(5,'Martin','C');

Create a Prepared Statement to SELECT Students data:

PREPARE pre_GetStudents (INT) AS 
SELECT *FROM tbl_Students WHERE StudID = $1;

Execute a Prepared Statement:

EXECUTE pre_GetStudents(2);

System view to check the Prepare statements of session:

SELECT *FROM pg_prepared_statements;