It helps to realize when and why it was created. The internal lore, as best I recall it is below... At the time, application developers stored settings in INI

It helps to realize when and why it was created. The internal lore, as best I recall it is below... At the time, application developers stored settings in INI files in the \Windows directory. Reading this name=value file was very slow. The registry was an attempt to centralize storage of that data, speed up application startup by reducing the time required to settings data from it, and to respond robustly to disk corruption. Of course, after it was created, everybody and their grandpappy (COM, MSI/Darwin, etc.) decided to abuse it as a general-purpose store. Now that XML file load is considered zippy enough to be done at application start, developers are encouraged to have a private configuration file in their own application directory and per-user ones in the per-user directories.