There are so many reasons to use a list! They help people understand that these items belong together. You may have a list of features for a product in which you would use an "unordered list" because it really doesn't matter in what order the items are displayed. However, if you are creating instructions, the order of the item is important so for this you use an "ordered list". The items in an ordered list are similar to the steps you need to follow to accomplish something. You need to make sure the end user follows the steps in a specific order so in these cases you use an ordered list that will display numbers instead of just dots, circles or squares for each item in the list.
When you need to create a list of items you use a bullet list. When you want each item to have a dot (or another marker) beside it, use an "unordered list". When you want each item in your list to have a number, use an "ordered list".
Now that you know how to create lists in HTML, you can move forward and learn how to create hyperlinks. Without hyperlinks, the internet would be very boring. You'd have to know the exact URL to every page you wanted to visit and type it in the browser bar!