Originally Posted by
Garthr
Seeing that I've ridden basic non-pinned/ramped double and triple rings my entire life without issues friction shifting the FD, obviously these "aides" are not necessary. Clever marketing would have you believe you can't live without them.
They are necessary when using indexed front shifting with a derailleur and shifter that don't allow trimming to eliminate scraping the chain on the derailleur cage. To make indexed front shifting idiot-proof, the shifter does not allow trimming; you're either in one gear or the other. To eliminate scraping, the derailleur cage is made wider to provide more clearance without scraping. But this degrades shifting efficiency, so pins and ramps are added to the chainrings to facilitate shifting even with a wide derailleur cage.