I think NBT means riding up the Troutbeck side...
Problem with the video and photos is it flattens it all out. Jacobs is very rocky, very loose and the top part of packed stone steps is at least 25-35% gradient.
The climb can be broken down into 3. Bridge to RH hairpin is very loose baby head rocks, almost impossible to get going again if you stop. Hairpin bend to gate is the easiest bit, it's a lot smoother, more dirt than rock. Gate to summit starts off with a bitch of a climb but there's an "easy" line up one side, still very steep but at least it's smoothish. The track then levels out, just a shale stone surface and anyone can spin along that. Then it kicks up sharphly, the surface getting rockier but much more packed and steppy with a couple of steep bends and then right near the top a couple of hop-ups.
No one part is impossible but stringing the whole thing together into one continuous dab-free climb is one for seasoned Elite riders only. Makes a great challenge though, seeing how far you get, competing with your mates as to who can do which bit etc.