If you are buying ads, you probably want something out of it. In most cases, you will be selling a product, and you want people who click on your ad to buy the product. So make it easy by pointing them in the right direction.
Someone searching for snow boots will click on your ad discussing the wide variety of boots you sell. They want to see them, but if, instead they see the home page of your site, they might just leave and go back to the Google search results page. That will be a waste of a click and however much money you bid for the click, in addition to potentially giving that business to a competitor. Instead of tossing away that cash, set the ad URL to go straight to the selection of snow boots, they are far more likely to make a purchase, which is exactly the goal of an ad.
Depending on your business, the landing page might vary depending on what someone searched for. However, it is generally a good rule of thumb that every ad should have a landing page designed specifically for people who click on that ad. This will ensure that more of your money goes towards ads that convert visitors into customers. For more tips on running AdWords campaigns, check out AdWords University: The Complete Guide to AdWords.