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

What can happen if you cause a postback is you can change the state of your controls, without meaning to. For example in using a gridview, if you postback during edit mode, you will no longer have access to your edit-ed fields.

Often you need to preserve the information from disapearing on a page when you hit the server, this is the point of

if(!Page.IsPostBack)