"We" being those of us in or around GPT. My Adsense day ends between 9 and 10 AM, and I always begin my day with yesterdays stats. Or "this month", since this gives yesterday something to compare with. Well, as of day 8, that is, so sometimes I start with "previous month".
Why don't they just give us "last 15 days" by default? That's what we want to see first.