WiFi bulbs don’t necessarily power on when power is restored after a cut; most zigbee bulbs do. Some people like this, assuming that the power outage represented a problem that they need to investigate. Other people hate it.
One community member has addressed the problem by creating a “Canary bulb” Smart app where if a particular bulb lights up when it’s not expected to, the app turns all the other smart bulbs in the house off. Again, some people would like that, other people would not.
You’re quite right that you have to have an RGBW bulb or LED strip in order to get color. Technically, it doesn’t have to be networked to get color, particularly the LED strips, but it turns out to be easier and typically less expensive these days to go with a networked device.
As far as switches to use with smart bulbs, see the following:
