Correlation of 0.25-0.5 being poor is very problem dependent.
For example, in difficult perceptual tasks ("can you taste which of these three biscuits is different" [one biscuit is made with slightly less sugar]), a correlation of 0.3 is commonplace and considered an appropriate amount of annotator agreement to make decisions.
Yes for certain things like statistical trading (assuming some kind of "nice" Gaussian-like distribution) where you have lots of trades and just need to be more right than wrong it's probably useful.
Not here though, where you are trying to prove a (near) equivalence.
For example, in difficult perceptual tasks ("can you taste which of these three biscuits is different" [one biscuit is made with slightly less sugar]), a correlation of 0.3 is commonplace and considered an appropriate amount of annotator agreement to make decisions.