Anyone that says, and there are many, that L2 doesn't mean anything, is a doofus. Like saying Sanscrit doesn't mean anything just cause u cant read it
L2 matters for sclaping, illiquid instruments, or afterhours.. but I would argue that the order book for very liquid stocks/futures/options/whatever.. mean shit, if the market is going to move.. it doesnt matter what the bids/offers sitting outside the money are. if you are an investor or swing trading.. do you really think you can find a better entry by looking at the book? and does it matter? i still have it on my workstation, but i dont trade based on it. look at SPY/ES today.. what would L2 tell you right before the first leg down?