The Enterprise wasn't really much at risk in "A Taste Of Armageddon"
That's actually fundamentally incorrect. If Scott had followed orders and lowered the shields, the Enterprise
would almost certainly have been utterly destroyed. Being attacked by disruptor fire capable of doing that and being given orders that make the ship vulnerable to such an attack, that constitutes significant risk.
I assume what you mean is that the Enterprise
outmatched Eminian technology, which is true. It's also true that avoiding the area would have eliminated the risk altogether.
However, the Enterprise
's mission to Eminiar was to find out why thousands of lives had been lost in the sector (quadrant [sic]) and stop it by diplomacy, in order to protect the much less capable ships expected to wander into the sector in the future and to ignore whatever code seven-ten keep-away signs were posted by the Eminians.
For whatever reason, not all ships were keeping away, despite the knowledge that ships were being lost there. Since the idea was to set up a port, it might be reasonable to suppose that Eminiar was in the middle of long space lanes. Ships in trouble might be forced to attempt to make port there, despite the risk.