Indeed, but will a non-tecnical user know that. It's been of increasing frequency non-technical users ask for disks to be wiped though, they are aware it contains sensitive information... but a light bulb? Maybe no lightbulb moment for them.
Either you trust the lightbulb provider to protect your creds better or don't use it. In my opinion the lifx is reasonably protected and far from being the worst offender here: the attack doesnt work over the air, and depends on physical access to a pre-setup bulb and involves physical labour to access the credentials (needs cutting out the board, removing protecting glue from the board, dumping firmware). This is not really mass-exploitable. Services like wigle will allow to see where the wifi is located though, but the bar for attacking is pretty high.
Have a look here for really awfull IoT sec: