I've looked at those in the past, but I've not made the jump because I didn't feel like digging into the box to put in a Decora-style outlet and wallplate.
However, that's become less of a consideration because over the last few months the mechanical timer for the ceiling fan has been failing to turn off automatically, so I'm considering going with an electronic timer, which has a Decora footprint, so I might as well change the outlet and the light switch to Decora at the same time.
And if I'm doing that, I might as well put in the outlet with the nightlight.
Great... I just went from a simple switchplate nightlight for about $15 to a whole new electrical set up in the bathroom for about $50.
sigh.