Two books with identical total gamma behave differently depending on distribution. Concentrated at one strike, the hedging clusters there and produces the pinning effect of gravity. Spread evenly, it applies mild pressure everywhere and pins nowhere.
That is the argument in one number hides the shape, and concentration is the specific property that decides it.
Why crypto books concentrate
Round numbers, and heavily. Strike ladders are coarse relative to price and participants cluster on psychologically obvious levels, so open interest gathers in fewer places than in a dense equity chain.
That makes crypto gamma effects more locatable than the small aggregate suggests: the pressure is weak overall and concentrated where it exists, which partly offsets the dilution problem.
The fragility that comes with it
Concentration means a small number of positions determine the shape. On a thin book one block trade can create or remove a wall, and a single expiry can delete a large share of the structure at once.
So a concentrated book gives sharper levels and less durable ones. Both follow from the same property.
How to read it
Look at the profile, not the total. Ask what share of the gamma sits in the largest strike, and what expiry it belongs to — because that tells you when it disappears, which is the discontinuity in what happens at 08:00 UTC.
A wall that expires tomorrow is a different object from one two months out, even at identical size today.