I use voice on my mobile/tablet all the time mainly due to failing eyesight and it is great - only catch is that it needs an internet connection to do the voice search even if you are searching your local device or using other voice recognition services
I use voice to text on messaging and email and it is generally brilliant - sometimes it fails hilariously but that is part of the fun.
TBH if you are using Google then you are being tracked to some extent so I wouldn't be overly concerned about them having recordings of your voice!
