Here's the main problem: People dont live in their Google Calendar. Your main value prop is: Know what you have to do in the next 48-hours. But the problem is, I have to go open up my calendar to see that with your app...why even install then, when GCal can tell me what I have up in the next 48h. The key would be for it to run in where I spend most of my day -- my inbox, not my calendar.
We do provide additional information not in your calendar, but I totally see your point, and we're working on this — in fact addressing this challenge is a key part of what we'll be tackling in our next updates to the extension.
Don't know if it has wide appeal, but I would love that.