I might be wrong in assuming that you might refer to a head shot taken at F1.2. If yes, below is my answer, if not; my apologies.
It is not about a cheap filter look; it is about having options when you need it.
Many assume that if I buy a 1.2 lens, I could use it only at F1.2
Reminder:
1 - depth of field is a function of distance. If people have been using it for a head shot at f1.2; that is their choice. I use my F1.2 when a full length person occupies 1/3rd of the screen. At that distance a dof of a 50mm 1.2 is deep enough. Believe it or not but under moon light, only that f-stop can save you from smear fat from a too high ISO without blurred movement.
2 - An f1.2 lens is a lot sharper at F1.8. Not because you bought an F1.2 that you will be shooting all the time at F1.2. In fact, I have Sirui F1.2 and I use it most of the time at F1.6. Finally, it is now time to be able to shoot with an auto-focus.
3 - having an F1.2 gives you chance to have that amount of light when needed, compared to not having it at all; cheap or expensive filter look.
4 - There are many things out there that don't care much about what is your dof. Flat surfaces for example; you can shoot them wide-open and dof is plenty enough.
Now, combine all four options and see if the lens might be useful to many photographers. I am sure that others have found other ways to use such a lens too.
Looking at an F1.2, or even F0.95 lens, I pay attention to sharpness, chromatic aberration, but mostly proneness to flare against the sun; then I decide if it is worth or not.
Having an F1.2 is about choices; compared to not having it at all. I wish Canon does the same thing at 20mm for example, without spending 2K.
I was joking a bit, but I do use my beloved 85mm f/1.2 II, to bring a bit more crazy example, even for street (preferably night settings), not only for typical head shots, often wide open. And this lens has really a small DoF distance in which a motif appears to be sharp. I then mostly shoot from a medium to bigger tele distance, and even complete people that then fit into the shallow DoF. But using such an extreme lens means that you really have to learn where it shines and where its limits are. Being undercorrected, this 85 shows a lot of lateral chromatic abberations in contrast rich settings - e.g. bright edges in light spots of night settings. Fortunately in the digital age this can easily be corrected by post-processing. But I never would use such a lens wide open in bright sunlight stettings, in fact, I'd never take it with me then. It is not made for lunchtime-in-the-desert settings
With my EF 50mm 1.2 it is a bit of a different story, since this lens delivers nicely sharp images when stopped down, and it is relatively compact and light. So it is much more versatile as a standard prime lens one can carry frequently in a handy gear. And like you state, you always have the option to go up to f/1.2, with widens the application range of such a lens. That's quite attractive.
Regarding F/0.95 and 50mm I guess you may mean Canon's classic "dream" or "nightmare" (depending on the reception) 0.95/50mm lens with the classic Leica M39 thread mount (LTM) - for many years the fastest lens sort of "mass" (not really) produced industrially. I have two Canon 7 bodies with a set of 1950s/60s Canon lenses, but I am no collector, so I never was interested in investing several thousand dollars in that monster 50mm that Canon mainly created to show-off against Nikon in their new rivalry back then (before, they co-operated for many years, Canon made the cameras, Nikon the lenses). At least with a classic manual focusing rangefinder with 47mm rangefinder base, like the Canon 7 that was designed for this lens, in real life you never have any realistic chance to get a non-steady motif intentionally sharp wide open, only by pure chance. So, since I still use these vintage bodies for film photography (the soft but precise and luxury sound of its titanium shutter is already worth it), I got Canon's wonderfully compact and light 1.4/50mm lens. It makes much more sense for real photography (Canon made also a 1.2/50mm back then). Of course, with a modern ML camera and all its little EVF helpers, you may have more chances to get a motif that isn't particularly standing completely still, in focus with a superfast manual focusing lens.
My experience with superfast lenses over many years is, in a nutshell: only with a precise AF they are really useful in real life.
