@Amigo- Why not feasible? A dimmer switch controls the power feed to the device-side wires it's connected to, a smart plug has the same wires available to it. There are also other brands out there that state they are dimming capable on a smart plug (such as the Treatlife brand), all of them have built-in switches to do on/off control of the power, why not have dimming capability? Seems an odd feature for a company like Kasa to leave off when they have a really diverse set of devices otherwise.

@Amigo- I'm not sure I would agree with the 'vast difference' part. An electrical socket is effectively just a junction in the AC lines of a house to a safe modular plug - you still have line, neutral, and ground. So if you have a dimmable smart-plug that you plug into a dumb and simple wall socket, all you've done is effectively add a new extension to the existing circuit that then has a dimming capable socket on it. The controls/components that make up a dimmer switch are housed by whatever body the plug itself is encased in.

This is really no different than having a dimmer switch in the wall that controls a permanently wired lamp or other dumb socket somewhere within the room - all you've done is made the dimming function able to plug in wherever you want it to be, as long as there's full AC power for it to start with (IE don't attach a smart device to something that's already being controlled by a dimmer).

@KriegTiger yes...I understand it can be done, but there's a big difference in "transforming" essentially, the level of output with a plug vs a switch. I'm going to safely assume we're dealing with LEDs here.
 

You're counting on a device that is either plugged in a wall or a strip, that can easily be dislodged, covered with something, come into contact with something that could cause a potential fire...etc to reduce and increase power output to a plugged in device. You dim a LED by decreasing the voltage it receives. This is what a transformer does. 
 

Again...it CAN be done in a plug, but it's much better, safer, and cheaper to do in a switch properly wired and secured into a gang box made  and designed to do such things. 

@Amigo- LED's make dimming a whole new problem (which seems like we're on the same page about), though usually that's handled by the LED device (E26 type bulb and the electronics in there). You can get some dimmable switches that specify being LED friendly though. The device I was hoping to plug into a dimmable smart plug was halogen lightbulb, no fancy requirements there.

I've been using lots of Kasa stuff already for managing a lot of my reptiles' needs; the power strips are fantastic for scheduling on/off, tracking power consumption to verify non-lighting things like heating pads are actually running, etc and minimizing dozens of different little timers and such that make cord management a disaster.

It was really the odd fact that if I search for dimmable smart plugs, kasa stuff comes up but the feature descriptions fro all the ones I looked at mentioned nothing about being dimmable. So I was hoping to get a concrete answer about it from the community since Kasa's own automated support channels were... less than helpful/clear.

Seems the answer is 'nope, they don't do dimming on kasa stuff, sorry'. Bummer, but that's alright - still good products otherwise.