The Plum Lightpad looks like a nice WiFi switch. That said, I haven’t seen anything that says it will “play nice” with a smart bulb. It will control a dimmable LED, but that’s not the same thing.
Unless there is special handling built into it, and again I haven’t seen anything to indicate that this is true for the plum, any smart switch, regardless of protocol, that controls the current to the light fixture that the smart bulb is in in is essentially turning the smart bulb into a dumb bulb. Because once the switch cuts the current to the fixture, the smart Bulb is powered off completely and cannot hear any network commands. This may still be OK for some use cases, but it means you always have to use the switch (either manually or via network) to turn the light on before you can give the bulb any other commands.
If there is some additional live current feature built into the plum for use with smart bulbs, please include a link for it. I may just have missed it, but I didn’t see anything on their site.
Meanwhile, the following discusses some of the other options for switches with smart bulbs.