Part of the difference between the Whole Life Challenge and any other daily habit logging app (or an excel spreadsheet, for that matter) is the requirement that check-ins every day are required. It's part of the fabric of the game, and it was built that way on purpose.
It might seem silly or frustrating, and can really be a challenge, especially when traveling, but we've found that one of the factors in the successful development of a new healthy habit is simply remembering to track it every day (not just doing it every day). Think of it as bonus - not only do you get to do it daily, you also get the added benefit of being required to find a way to enter your score into the WLC website. It will make the likelihood of your success that much greater. And, whether you like it or not, it is one of the rules of the game.