1 Fate for the Secrets of Devils is a Great Deal, however
There are a few choices out there needing a few tidbits of Fate to unlock promising secret knowledge. One that has caught my eye very early on is the Stealth Watch Repair requiring the Albino Rat.
After all, what could the devil's be up to fiddling with someone's watch? An explosive plant, maybe? The rare success result from the Talkative Rat in particular gets the imagination running. How high could the devil's Baroque stat be going into this Stealth Watch Repair gambit?
Turns out not that high at all. Not to say the results you get from this choice is not eye opening! It's actually a very substantial amount of text you get for only 1 Fate. There are few places in Fallen London that has this much text. And after reading all that, you will be like "Ah! But of course! How could it be anything but that? It's always that way with devils." Surprisingly, with the rare result of the Talkative Rat, he is actually on the right track. But, not in any way you can actually guess.
I would say this choice is a steal for only 1 Fate. It brings new light to other operations of devils like with the Intimate with Devils quest line. Why they would go through all that effort for a single soul when regular souls go for 2 pence pittance, and you can only rightly expect your soul to be brilliant which only goes for half an echo. It certainly widens the scope of devils beyond that of simple illegal spirifier activities.
So yes, I would say this option is for sure worth only 1 Fate. Definitely worth 3 Fate. Maybe even 5 but that would depend on the rewards, wouldn't it? I, however, don't remember the rewards for this Fate content so I can't say. I can say, though, that intangible tangible Fallen London goodies definitely aren't the point of this Fate content.