Sure, it was hard to find time every day. Sometimes I got up early. Sometimes I stayed up late. Sometimes I squeezed it in on a flight. But I pulled it off. I had enough flexibility within a day to find a little slice of time.
As far I can, the author advocates the exact same strategy, they just use a week as their unit instead of a day. I don't see how it's that different otherwise.
Personally, for me, I think a week is almost too long of a cadence. I've been exercising lately and I stick to a weekly schedule with that and I find myself tending to slack until the very end of the week and then cramming it in. A week is long enough that I don't get really get in the groove and feel like it's a continuous habit.
But, of course, everyone runs at a different rhythm. Find the one that works for you.