Implementation of IsPostBack in page load

Question

The more I use ASP.NET, the more if (!IsPostBack) {} seems pointless...

First example:

For example, I just Googled an issue, they said use this

Answer 1

protected void Page_Load(object sender, EventArgs e)            
{
    if (!IsPostBack) { 
        SqlConnection conn = new SqlConnection("Data Source=-----; Database=-----; Integrated Security=True");
        SqlDataAdapter da = new SqlDataAdapter();
        conn.Open();
        da.SelectCommand = new SqlCommand("Select Command",conn);
        conn.Close();
        DataTable dt = new DataTable();
        da.Fill(dt);

        ddlSearch.DataSource = dt;
        ddlSearch.DataTextField = "---";
        ddlSearch.DataValueField = "---";
        ddlSearch.DataBind();
    }
}