When I started with electronics, aged 12, as a self-taught kid I didn't know any better and bought a big Weller 100/140 watt soldering gun with pocket money saved up over a long time. Soldering small electronic parts with one of those was good practice and trial by fire, for sure!
The BGA thing was done using the camcorder and an external monitor - the image above is from the camera. That kind of detail work is too small for the visors, at least with my eye sight. But soldering "normal" SMD components is definitely achievable.
The 7" measurement is my personal distance - I measured it this morning. It is possible to use reading glasses under the visor to get even more magnification, but it is rarely necessary.
Getting smoke up your nose is an issue with a visor, for sure. I'm thinking a small fan or extractor near the work piece would help, but I am able to work around it so haven't bothered yet.
I usually get the PCB I'm working on up off the desk by 12" or so with a PCB holder / vise. That way I don't have to hunch over it.
If I was assembling large PCBs constantly, I would definitely want a more professional solution, e.g. a Tagano or a microscope, so I could sit comfortably and work for days, weeks, and months.