According to the Minnesota Stormwater Manual:
“Curb Inlet protection devices intercept and/or filter sediment before it can be transported from a site into the storm drain system and discharged into a lake, river, stream, wetland, or other waterbody.
These devices also keep sediment from filling or clogging storm drain pipes, ditches, and downgradient sediment traps or ponds.
Inlet protection may also include placement of a barrier to create a bypass of an inlet transferring flow downstream to a sediment trap, basin, or other inlet discharging to a non-critical area.”
Nothing wrong with sediment control BMPs, as they are necessary tools in an effective erosion and sediment control system. However, they don't “filter” much sediment.
When properly installed, these allow for ponding of water which allows larger sediment to settle out, keeping it out of the storm system. This is a good thing, but doesn’t necessarily prevent water quality non-compliance caused by fine, colloidal particles.
However, I do like this statement in the manual : “Caution: To the extent feasible, erosion prevention practices such as stabilization are preferred to sediment control practices.”