I used to feel the same way you do - it's to save money; but also there may not have been enough room to add an extra digit without making the LED display smaller. But I've changed my mind when the P10 was released. The P10 only allows you to set a maximum time of 10 hours. The P10 has the room to display longer times than 10 hours, but the user is not allowed to do so. So I also have a feeling that it may be do to some insurance or other legal liability. Such as allowing the end user to leave the smoker unattended for too long.
I have had problems of forgetting to reset the time on the P10. So now I set a timer (either kitchen or my iPhone) to go off after a certain amount of hours to remind me to reset the P10. Or if it is an overnight cook, I will reset the time just before going to bed.