There are two primary use scenarios.
In the first individual record variants are used in isolatation for UGens having many inputs where default values are required
In the second graphs are predominantly constructed using record syntax for clarity.
In the latter case clarity is greatly enhanced using record field disambiguation as is present in ghc since version 6.8.2.
The record variants are generated by a program using the database at hsc3-db and are not stored in the darcs repository. This database is auto-generated from the supercollider language unit generator bindings and is not entirely accurate.
In particular neither argument re-ordering or multiple channel
collapse are correctly annotated, see for instance the Out unit
generator in the help file
analog-bubbles.hs, where explicit bus
numbering is required.