Why are you all being so narrow in your requirements? Fawkes was caught and then gave up his co-conspirators. Isn't that useful and accurate information?
This is such a circular claim. What information did they have about the co-conspirators that wasn't obtained through torture and confessions? You're relying on a story obtained through torture to validate the effectiveness of torture.
The historical use of torture has been to extract false confessions. The only countries that engage in systematized torture do it for that reason.
Let's look at how they caught the conspirators:
Anonymous letter hints at the plot. Searches are started.
First search, they catch Fawkes with firewood. Fawkes mentions the name of a known Catholic agitator, Percy. Second search catches Fawkes in the act. Now they know both Fawkes and Percy are involved, no torture.
Fawkes is interrogated, gives up nothing. They learn his name from a letter addressed to him that was on his person.
The next day, the servants of Rookwood are interrogated. Rookwood was chosen because of his relationship to Catholic agitators, Fawkes had still revealed nothing. Those servants gave the authorities the names of many of the other conspirators: Catesby, Rookwood, Keyes, Wintour, John and Christopher Wright, and Grant.
The rest of the conspirators are fleeing and begging friends and family to help them raise an army. They get denied as people don't want to participate in treason, meaning there are literally dozens and dozens of people who are now witnesses to this specific group of people essentially confessing to participation in a plot, the news of which is now spread far and wide.
Most of them are captured by a company of 200 troops who followed their path - which was known not from torturing Fawkes, but because the morons were publicizing their presence as they went.
THEN they start torturing people. Only Fawkes had been tortured before they were all captured, and Fawkes had no idea where they were.
Now, notice how the torture worked: they had a bunch of information from a ton of witnesses, so when they said, "Were you part of the conspiracy, we have proof that you were with so and so..." The tortured party, just admitting to whatever they needed to, was simply agreeing to information obtained by other means.
In fact, it's all the information obtained from the torturing - the extended networks of the conspiracy - that is the LEAST useful information in the gunpowder plot. The confessions were suspicious, with different handwriting between the narrative and signature.
What value did the torture add? From the state's perspective it allowed them to drastically expand the conspiracy so they could break the back of the Catholics. This is what torture is great for, but what evidence validates the stories that were told under torture?