ah yes the clutch derailers.
Shimano marketing is clearly aware that the average rider's need for 10+ cogs is tenuous at best.
They encourage you to upgrade by withholding clutch technology from trickling-down to lower numbered drivetrain speeds.
my 7s bike has worked just fine without it, a slap guard on the chainstay to keep the paint from chipping, and a simple chainguide on the front ring as insurance against dropped chains.
Now, I actually do possess a clutch derailer on one of my other nicer bikes. It definitely prevents chain slap. Not a clear game changer for practical value though vs the older way of dealing with it...