Simple and useless. You can have any system you want for your personal use, but clocks and calendars are for colaboration. It's nice that you have day and night hours on the clock where you are. No you will travel a few thousand kilometers. You know your decimal time you get there, do you know whether it will be daytime or nighttime? You get there, and it is winter and the dark time is 3x of the daytime. Have you got any idea when anything opens and closes? And why have weeks if you don't have months. How about just numbered days?