The exam date is fixed. Your evenings aren't. The app knows how many days are left and how many hours you still have to do to get there. You just have to show up on the evenings you pick, and not on your own.
When you study while working you have few evenings and no slack: if you skip a week, the pace you need goes up and you see it straight away. It isn't a telling-off, it's arithmetic: the hours left divided by the days left.
You do your sessions with another person on the call, so on the evening you don't feel like it there's still an appointment, not just a good intention.
It divides the hours you have left by the days remaining until the exam date you set: the pace you need recalculates itself after every session, based on what you've already done.
Nothing automatic: the app simply recalculates the new pace over the days that are left, so you see the real effect straight away, not a judgement.
Yes, the countdown and the pace calculation also work with the timer on its own: coworking is an extra option for the evenings when you need an appointment.