TL;DR: Very situational card, only for rogues that use and skills and with a good amount of "succeed by X" triggers.
Let's compare it to the other Rogue Tarot card as they compete for the same slot: The Moon • XVIII
The Moon • XVIII gives you a solid +1 for 3 resources and 1xp, with no competition to other slots.
Knight of Swords now, gives +1 on any skill, IF you succeeded, therefore:
Knight of Swords can be used for any test, so more aimed at Rogues that would use at least 2 different skills with "succeed by" triggers, as of now, mostly and skills.
I am not going to do a list of every single combination, but a selection of some interesting that came to my mind:
Switchblade for higher extra damage rate
Sawed-Off Shotgun for more consistency in high damages shots.
Great synergy with Opportunist and the upgrades that DO help to pass the test
If you plan to use the "succeed by/succeeded by" mechanism AND would like to use multiple skills (/ based on the cards we can see in the selection that use this mechanism as of the release of this box), then Knight of Swords could be a good pick, otherwise select a lvl 1 tarot card that also help you succeeding the test.
Let's bet here that the new Rogue to come will be a reversed Stella Clark? Succeed by 3 or more and get an extra action? In this case this card could become a stappler.