Tty for serial port to Arduino from Linino

Sorry for my ignorance, but I do not get the point of what noblepepper is suggesting:

Changing inittab to comment ash start, was stated to be dangerous (I don't know why because I still was able to connect via YunTerminal). And having a sketch sitting and waiting to get Linino started is also known practice. In what way is changing rc.local to reduce chatter an improvement?