“Though Voice Search may not offer as many features as Assistant, it still supports more languages and is relatively easy for a quick Google search”
The Google Search home screen widget has silently undergone a design change. The microphone icon to trigger voice search has now been replaced with Google Lens and Discover. Since this is a server-side change, it might not be available to everyone right away. Moreover, Discover and Lens can also be useful tools as the former allow users to find more relevant and personalised content, while the latter can recognise objects just by pointing out the Lens camera. Though Google Voice Search may not carry as many features as Assistant, it still supports more languages and is relatively easy for a quick Google search.
However, nothing has changed on the embedded search bar in the Pixel launcher and other stock launchers that come with Assistant shortcut for quick access. The motive behind replacing Voice search isn’t exactly clear at the moment but seems like Google wants to push Assistant for any queries and searches, so this change might be coming to all devices in the future. At this point, it isn’t clear when Google would roll out the change publically.
Fortunately, Reddit user u/andyooo has found a workaround to use voice search from the home screen — hold the Google app to see voice search option in the long-press menu, then press the voice search option to drop a shortcut of the same anywhere on the home screen. Alternatively, one can also tap open the Google Search widget to access the voice search option.