I think both the Lifx and easybulb can be used without a remote just a normal switch.
I guess you can, but you will lose all of the 'smart' features. Once you have turned the light off with the existing switch, the power is interrupted and you can't control the light until the switch is turned back on - If you want to retain the web control you need to leave it turned 'on' all the time and only control it with the iPhone. I can't find a manual, so it is possible they have implemented a feature where turning the power off/on quickly could toggle the light on/off, but sooner or later someone will forget and leave the power off.
Still, they are pretty cool for a retro-fit in specific situations, say a home theatre