This is definitely bad as a 1-cost card, and feels like it should be 0. If you have to pay just to swap your THW for ATK, you are better off just playing any other cheap event that deals with threat. Chase them Down comes to mind. While it is situational for sure, I would say this card is also situational. It needs to be in your hand at the exact time a problematic side scheme is in play for you to be able to spend 1 and then make use of it. The prospects are not good. Easily houserule-able to either cost 0 OR be an upgrade that can remain in your play area with the ability 'Action - Attach this to a non-permanent side scheme'.
I should also point it is a double-edged sword in multiplayer with regards to allies. While some allies have better ATK than THW, especially in Aggression, an equally high number of them are fine with their thwarting prowess. To use this card on a side scheme and empower your own allies could mean de-powering other players' allies, which makes it very awkward and probably not worth the slot in your deck.
To make the most of the card, you really need to be leaning on that ATK boost, which is present in Aggression for sure. From Aggressive Conditioning and Combat Training to more special cards, like "Now I'm Mad" and Fluid Motion, there is synergy to be had for sure. The question remains though, will you be able to maximise the effect by having the card in your hand at the right time, when instead you can just go for a direct thwart effect?