Bixby can dictate
Samsung Keyboard can dictate (it does it better with more language support)
Google can dictate (but steals your data)
Which one should I use? Samsung keyboard voice is great (it provides better performance and support for Russian voice dictation)
What annoys me (Bixby dictation uses the Bixby button, but I want it to use the superior Samsung keyboard dictation instead, why make the same feature twice? By 2 different projects?
Why not Google (I think it's time google gets out of the Android world, they did great, but now they're doing more harm than good <edit>
You can still use the samsung keyboard with Google voice typing on it. You have to have the Google app enabled however. Once you do, go to settings, general management, voice input , change it from Samsung voice input to Google and there you go. You will see that next time you open your keyboard, you will have Google voice input on a Samsung keyboard.