> Why not?

It seems like you weren't really asking, but I'll answer anyway.

It's bad security practice, and opens up your network to attack and/or compromise, you're massively increasing the attack surface, and a compromise of one of those components leaves the attacker sat on your edge router, at which point your entire network is fair game.

Generally speaking you shouldn't expose anything on your edge router / firewall, it's a safety barrier.

You can sit things behind it in a "DMZ" and port-forward and isolate them etc so that there's no packets terminating on the actual edge device itself.m, that lowers the risk of a full network level compromise.

Chances are you might be fine and never have a problem, but it's still recommended against.