Originally posted by photoptimist I see large aperture lenses this way:
I think the points you listed pretty much cover everything. Main uses of fast aperture these days is a) You can take photos in low low light (and AF will work, as well), b) you can take photos with really really shallow DoF (which can be artistic, or it can be gimmicky)
Another problem is that really fast lenses have such shallow DoF that AF might struggle. This is why Nikon is not producing f1.2 AF lenses, and even Canon's f1.2 are really rare. Pentax barely makes a couple f1.4 lenses. But Pentax' f1.4 lenses are generally still quite compact, which lots of people appreciate.
What point is buying an expensive Sigma Art, with its high optical correction and fast aperture, if you always leave it at home, because it is too heavy to carry around on trips? Better to have an FA 50mm f1.4, which still delivers decently sharp photos and good brightness, but can fit into a camera bag easily.