It’s ingrained and arbitrary. The only thing we’ve found so far for measuring time that doesn’t appear to be arbitrary is Planck time, which is so small it has no use in daily life. So if you have to use an arbitrary unit anyway, why make a new arbitrary unit? And while the second, minute, hour, and to a lesser degree month are arbitrary, days and years are not, they are just based on the unique circumstances of when we started observing our world in a scientific manner.
It’s ingrained and arbitrary. The only thing we’ve found so far for measuring time that doesn’t appear to be arbitrary is Planck time, which is so small it has no use in daily life. So if you have to use an arbitrary unit anyway, why make a new arbitrary unit? And while the second, minute, hour, and to a lesser degree month are arbitrary, days and years are not, they are just based on the unique circumstances of when we started observing our world in a scientific manner.
Seconds are defined as one gazillion times the Phase transition of some caesium atom, not the planck time.
Otherwise you are correct.