What's the difference between WiFi and Airplay speakers?

Will WiFi speakers show up on my AirPlay list of devices even though they are not AirPlay certified?

And, if so, will I have the same functionality.

What's the difference between WiFi speakers and ones' that are AirPlay compatible? Is it simply certification and compliance guarentees?

Before someone says no, consider my Bluetooth lightbulb speaker that is a selectable as an audio output in my list of AirPlay devices as long as I'm paired to it. It is not sold as an AirPlay compatible device.

But who wants to do that when I can have multiple devices streaming to multiple audio/video devices without connecting and disconnecting Bluetooth devices.

Also keep in mind in my opinion you have to pick your poison and we've eaten the Apple. So, for better or worse, we use Apple devices.