openSUSE Aeon does not have a firewall, is it necessary?

While reading a topic on the openSUSE fórum about the lack of firewall on openSUSE Aeon, I wondered if this immutable OS really doesn’t need it and if working with boxes is enough security to not implement it.

I am a novice in this topic, how serious is it, would you use it?

If you have something like a pfsense in front of your ISP provider, you can get away with not having a firewall, I guess.