Because vanilla Generals isn't good enough for you. Realism overhauls and graphical enhancements are the main points of existence of this mod. If you want tons of new units, this is not the mod for you.
For those who don't want any spoiler update, skip this part. The smoke screen effect when a artillery is firing will be applied to most artillery-like units.
PLA Typhoon Launcher is available only for Fai aka Infantry General.
It serves in role as heavy artillery support like Nuke Cannon, only its firing power is lesser but more missiles to spare. Its missiles when explode, leaving small fire field to do extra damage against most units. In total, more chance to hit several targets in larger area, longer firing range and less dangerous when exploded.
Youtube version: Youtube.com