Grendel_Khan
Hero
Sure, you definitely don't need them, but in some cases mechanics can help move things along, and get players making more risky decisions, rather than turtling or only doing what they're optimized for. Even stuff like getting rid of passive Perception rolls can help--players have to take more actions to figure out what's happening in a given situation, or just act boldly with incomplete information, rather than squinting and peering until they intuit what the GM wants them to know.I don't think you need special mechanics for things like this. I thing traditional RPGs do things fine as long as everyone is on the same page.
Making lots of decisions can be daunting as a player. It helps when a system gives them a nudge, including changing the way you think about a "failed" roll (but obviously that's not a requirement).