A digital camera sensor and a traditional spotmeter both use photo-electric sensors with (very close to) linear response to light. Film, on the other hand, uses photo-chemical sensor with a response very different from linear. As a matter of fact, the response of any given film is very different from any other film, that's what makes them unique.
The histogram is a graphic representation of electrical signal as a function of the intensity of light that hit it. The same as needle sway on the old style light meters and the same as the led readout on the newer light meters. The ability of the photographer to understand and correctly interpret that data according to the film used is what makes the instruments useful.
If I am missing something about spectral response of a traditional lightmeter, its dynamic range or perhaps even its reciprocity awareness, I'd like to hear a little more about it than witty one-liner soundbytes.