His intuition was that it would be between 48 and 128, and he's patting himself on the back that his calculation resulted in a number between those? Those goalposts are super far apart!
That's pretty close for what was basically an off-the-cuff estimation. He chose those two numbers because their use in the real world gives him a reasonable point of reference.
The calculated value of 74 bits is pretty close to the mid-point of his estimation.
His intuition was that it would be between 48 and 128, and he's patting himself on the back that his calculation resulted in a number between those? Those goalposts are super far apart!