The psuedo-TTY subsystem is designed to allow user sessions with virtual, rather than hard terminals. Telnet, ssh, terminal emulators. It provides everything you would expect from a tty. Cooked mode, baudrate control (despite redundant), all that jazz.

Its purpose is not just to make isatty return true. If you spin up that giant subsystem to trick an application into a different behavior on a simple pipe, then I believe it is appropriate to call it a hack, trick, workaround or similar.