One could certainly argue that some animals (horses, camels, rhinoceros) have teeth that have parallel ridges like that... but in every at-height industry I'm aware of, only the devices with conical, pointed teeth are called "toothed" devices.
The ridges are much more rope friendly. More prone to slipping on a drop, but that's really not an issue with a foot ascender. A drop doesn't shred the sheath like a toothed ascender, and all but one rope I tested, they just slide down the rope and bunch up or wrinkle the sheath a little. I use one of the ridged cam rope grabs for a backup when testing some equipment for dismantling ham radio towers, and can attest to their habit of very rarely doing any rope damage.
Seems like a better cam design for a foot ascender, to me.