Why do ports 8888 and 8388 need published and not just under "expose:?"

[FueledxJarritos]

recently came across the "expose" directive for compose files for when you don't need to access that port outside of that docker network. so if i dont need to access a container, i can just put it under "expose:." I'm not super experienced with docker and esp gluetun, so maybe these are stupid questions.

• If i'm not port forwarding and exposing a port to outside of my home network, does it really matter if these ports are published in the compose file and not exposed?
• Do the ports of gluetun 8888 and 8388 need published outside of that docker container? What outside of that container network would need to go through those ports?