Ok in when you have docker-compose.yml you can have sometime 5 times the same password or name or value whatever, when you wan't to edit or change this value you need to change it 5 times normaly but when you have .env in the same directory where is you docker-compose.yml you can have in your docker-compose some value like : $DBPASSWORD or $MYID or $PATHDB and in inside your .env file you need to do something like this : DBPASSWORD=helloiamDBpassword
MYID=IamTHEID
PATHDB=/root/Config/MYDB😅
You change one time the value in .env for all the time the value is needed in your docker-compose
When you have multiple machine and you use ansible or pssh you could simply juste do docker-compose up -d and all docker-compose start with différent value ;)
And my i think having file like .env (or use the same .env i have now) with native netmaker could be insane, when change something or add new node or clean install a node or whatever i am sure my node gonna have the same ip or the same hostname for dns ;)