First. If you don't understand what's something is for, then you probably shouldn't use it. 90% of people selling things are flogging useless stuff to people who don't need it.
If you are not sure whether something would benefit you or not, then for heaven's sake, don't abandon your existing working practices. If it aint broke, don't fix it.
In very simple terms ADO.NET is something that lets programmers write programs that access some kinds of databases (or just get some data from somewhere). There are plenty of existing alternatives for this and it certainly isn't something revolutionary. As I said: if it aint broke, don't fix it.