2. They are not drivers of transmission
Children both catch and transmit the virus less than adults.  
In fact, living with children has been shown to reduce the risk for the rest of the household. Studies have shown those over 65 living with children are less likely to be hospitalised from Covid-19 than those who are not. 
We also know that schools are not drivers of transmission.     Teachers are actually at a lower risk from Covid-19 than the rest of the population, despite their daily close contact with large numbers of children.
It’s safer to wait