Is this normal for single hop ales?
Maybe for brew dog it is, and homebrewers at my local club have done this.
I only use dry hopping for my single hop ales occasionally, when the hop has promising aroma qualities to it. Is there a point to do it even if it's not typically an aroma hop?
All Hops have aroma and flavor, just some are better then others, or some that give off an aroma that is desirable to the brewer. Its personal preference.
On some notes for dry hopping and the amount used. may not be relevant to you .
From my research on dry hopping, if you want more hop aroma and flavor, you have 2 ways of achieving it
Method 1) Less hops for longer in secondary/aging/conditioning
Method 2) More hops less time in secondary/aging/conditioning
The research below shows within the first 24 hours, majority of hop oils get extracted, then plateau off but still slowly extract the oils. Also it is dependent on hop variety and humulinones, iso-α-acids, α-acids
Is there a saturation point for these oils where no perceptible change in flavor or aroma? Maybe, but I could not find any research papers or studies done.
Also I can't speak for brewdog and why they use so many hops, but it looks like a "go big or go home" mentality with single hop brews.
dry hop research