On a daily chart, you can get volatile price fluctuations as a base is formed. Weekly bars consolidate those fluctuations a little better. Weekly charts also provide a fuller snapshot of a stock's history. That's because they reached those peaks in March 2000, when the market last topped. Most daily charts can't fit enough data on a page to track a stock that far back.
Weekly charts offer other pluses.
Institutions often take several weeks or months to build full positions in a stock. Brisk-volume weeks that end with a stock closing in the upper half of its price range often signal heavy buying by the big boys. When a stock breaks out of a sound base and heads for new highs, weekly charts can also serve as solid confirmations. Getting a big intraday volume spike as your stock zooms out of its base is always a plus. But when weekly volume exceeds most prior weeks, you could have a big winner on your hands.