Historically I've mainly worked with simple latitude and longitude coordinates in a SQL Server. I stored them as a geography datatype in SQL Server, and rendered them on a variety of displays (primarily Google Maps).
Recently I've started working with shapefile datasets from various sources, and almost exclusively they are geometry. Further, they use a variety of coordinate reference systems.
It's pretty maddening to work with.
- The USGS, for some of their data, use a very rare and hard to ID CRS.
- The county of Los Angels says they use the State Plane 5 (without reference a CRS specifically), and of course there are multiple "state plane 5's" to choose from in QGIS.
Are there really some advantages to these particular spatial reference systems that cannot be achieved by sticking with WGS84, considering that the VAST majority of people viewing and consuming will want it in that format?