Spiral stairs are a specialized solution to accessing another story or level. Theaters and equipment mezzanines are the main uses for a spiral stair. A residence in need of a little drama is another use. 
Benefits
Besides being aesthetically cool, spiral stairs have some key benefits. They have a very small footprint, rivaling a ship's ladder. Spiral stairs are extremely functional. None of their structure is excess, everything works together. For the architect there is no detailing to do, just a layout and selection of parts from the manufacturer's standards. Finally, spiral stairs are fun to use - at least for a while.

Utilitarian Stairs are used for fire exits, industrial buildings and and other "backstage" locations. These stairs are almost always steel because of the building's Construction Type or the configuration that the stair must take.  Steel allows for bent stringers, and balusters that will hold up over time. 
The drawings should show a stair cross-section at the very least to establish dimensions of the flights, headroom clearances, support and railing configuration. Additional details should be used to show any aesthetic or quality-related issues. Stairs are normally fabricated by specialty sub-contractors, so for the most utilitarian of stairs the only information that they need are the dimensions. The stair will be truly utilitarian in appearance.
An otherwise utilitarian stair can be made more attractive if attention is given to flooring, railing, and exposed connections. Carpet removes some of the industrial appearance. Replace the standard 4" o.c. pickets with something nicer. Add aluminum hand rails, which do not require maintenance to remain unblemished (finger rings tear up painted steel). Use a drywall soffit on the underside to cover most of the remaining utilitarian aspects.

Guard Rails and Handrails are needed in several locations in buildings - stairs, ramps. mezzanines, floor openings, etc. The building code and ADA accessibility regulations have an impact on placement, heights, and configuration. 

In most occupancies any openings in a guard rail must be small enough to prevent the passage of a 4" sphere. Vertical pickets are the simplest and least expensive way to accomplish this. Other methods are a low wall, grids, panels of expanded metal lath and glass panels.

Hand rails are limited in profile and circumference. A painted metal tube/pipe is cheapest but has the drawback of being easily scratched or worn by hand contact. Wood doesn't show this wear as easily, nor does an aluminum or stainless steel tube. Often these round shapes are fastened to a U-shaped channel by a fastener on the underside. Here wood is shaped to fit a flat surface for attachment.  See the Comment paragraph for download link.