The widest aperture of any lens is considered to be one of its most important features: it is even thought necessary for this statistic to be a part of the name of the lens (eg Nikon f/2.8): why?
The answer generally given is that 1) a wide aperture lets more light into the lens and enables photography in low light, and 2) a wide aperture gives a narrow depth of focus. Technology moves on, and cameras now by and large have the capacity to use very large ISOs without significant noise; this to a large extent makes 1) above an out-of-date concern, especially as increasing the ISO does not have any effect on the artistic effect of the image, whereas increasing the aperture does, and might for example produce an image with a very narrow depth of field where that might not have been desired.
Therefore, in effect, the low f-number is there only for one purpose – to enable the photographer to focus on a single subject, leaving the remainder of the image with a pleasant blur (the “creamy bokeh” which sends so many photographers into uncontrollable extasy!). This purpose is occasionally of importance for landscape photographers, but more often for the portrait or street photographer, who wish to cut out extraneous details; for wildlife photographers, usually equipped with a long lens, the problem is usually the other way around – they would like more depth of field to get an entire animal in focus, rather than just one part of the face; and the same situation holds for macro photographers. I would therefore say that having the lowest possible f-stop is only crucial for certain photographers and in certain situations, and presenting it as the defining feature of a lens is out of date. To be clear, important in varying degrees in various situations for different kinds of photographer: but not the one defining feature any more.