I'm not sure if this applies to dictation but when I was setting up this Win 10 laptop for the first time, Windows was prompting me to download the Windows Launcher for Android so I could seamlessly share files, calendar and Cortana more between my Android phone and my laptop.
They didn't say that the Win Launcher would change the entire look and feel of Android, so someone with less knowledge would get a shock when they find their phone transformed. MS is trying to backdoor it's way onto Android.
I played with the MS Launcher about a year ago. It actually is not half bad and I might be tempted if I was a businessman. But Cortana is limited compared to Google Assistant.
I have both turned off.