there's 86400 seconds in a day. If we use a new unit that is slightly shorter than a second as a metric second, we can do 100000 metric seconds a day, with 100 metric seconds per metric minutes, and 100 metric minutes per metric hour, and each day having 10 metric hours.

Your 1 hour activity now takes 0.5 metric hours (it might be 20% longer, but that's arbitrary anyways, we rounded them to the closest hour anyways)

We are only used to the current system because we have been using it.

"Hey sweetie, please come home by Hour 89.58333333/100 otherwise I'm gonna have to ground you for a week, love you!"