It's targeted to oil-based products, because those are the ones being applied to decks year after year. The result is clean wood with which to work. One way or another, you have to clean a deck before you coat it. Deck coating products are made to get into the wood and keep other things out of it. Some cleaning jobs are easier than others.
Barbecue grills are almost standard fixtures on most decks, and that means splatters of grease.
Before you start removing old finishes, get rid of the grease and other contaminants. For hamburger grease, for example, in most cases all you need is a bottle of shampoo that's formulated for oily hair. For large areas or extremely heavy globs of grease, you may have to go to a commercial degreaser. Remember, too, that after you clean a deck, you have to allow time for it to dry thoroughly. Don't rush this part of the job.