From a parsing perspective, you can use the first keyword to branch to the proper parsing expression with ease... e.g.: If the query starts with "SELECT" I can

From a parsing perspective, you can use the first keyword to branch to the proper parsing expression with ease... e.g.: If the query starts with "SELECT" I can use the SELECT parser. If it starts with "UPDATE" I can use the UPDATE parser and so on. With FROM/WHERE/SELECT you can no longer do that. So there's a cost... but to be honest, it's worth it in my opinion.