The link spectral efficiency of a digital communication system is measured in bit/s/Hz.
We have that 1 Hz = 1 s$^{-1}$.
So, $\left((1 \,\text{bit}) /1 \text{s} \right)\, / \left({\frac{1}{1 \text{s}}} \right) = 1 \, \text{bit}$.
Thus, why don't we just say then that spectral efficiency if measured in bits, but wherever I read it's bit/s/Hz? Is there some special meaning to this?