I guess you are talking about bringing up Google Calendar on the web browser? If I need to look at a calendar while not at a computer, my phone has a 4x4 month view widget on it, that while small, with proper color coding is actually a pretty good indication of what's going on on any particular day (purple: family; red: hockey games; blue: work--actually I further color code work into blue, green and yellow). If we need to look up details for items on a particular day, I just click the day. No 2FA at all. And of course, even when we are both in the car, the passenger would be the one doing all the clicking and searching. The driver would be, well, driving!
Like I said, it's just me, but I really don't see much of a use for this, but I won't say that some people like yourself don't.