Fast lenses had more utility when people used film cameras (and for those who still do). Slow ISO--ASA for those of my generation--required wider apertures. But with today's digital cameras capable of not just usable but superb images at stratospheric ISOs, high speed lenses are really not a necessity. They're more of a fetish. The out of focus elements are now treated with the same importance of the main subject by some photographers. I'm not sure what constitutes "great bokeh". To me, if the background is not distracting, it's what it's supposed to be.
Despite all this, I still have several fast lenses I really like. They are versatile in their abilities. They have that "look" when shot at wide apertures and they are very, very sharp when stopped down to smaller apertures. In the end, I still prefer a photograph that emphasizes the subject and the light over one that just shows how a lens performs.
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