A blood alcohol level of .05 shows impairment similar to someone who has been awake for 17 hours.   Should we also make it a criminal offence to drive if you've been awake longer than 17 hours?
.
In an ideal world there would be no traffic accidents and no impaired driving.  But IRL we need to make trade offs in how we spend time enforcing our laws to ensure we receive positive returns for society on the money spent.
.
Criminalizing people who have no more impairment than someone who has been awake all day is not a way to do so.