Thematically is the “Enemy Observance” ability supposed to be sizing up an enemy in the midst of battle, or taking the time to observe an enemy from a distance before engaging them? The use of an action implies that this is intended to be used in combat, however I like the idea of a sneaky character identify enemy traits before engaging with them, sizing them up in advance. Is this ability intended to cover that scenario, or is there another ability that would be able to engage this sort of tactic?
On one hand we have to mention the “time” it’d take to be able to assess the capability of the creature, so that it could be applied in an encounter such as a combat. Thus, using it in combat it’s take you an action to get the information from your target.
However, that being said, like you I’d imagined it being used as part of a reconnaissance effort. Perhaps as a precursor to battle, but also something that might just be someone peering around a tree or over a hilltop to see how the target behaves and such before deciding if they’d be able to overcome it through physical means.
So I would say the Ability could be used/useful in both situations.