Focus Assist is not new for Windows 10 – in previous feature updates for Windows 10, it was known as Quiet Hours. When this name change was announced, the general reception was that it made no sense and the Quiet Hours name was more than adequate for the feature.
I have long felt that the April 2018 Update was focused — no pun intended — on productivity and that is how Microsoft explained this name change:
Focus Assist helps you get more done by easily blocking notifications, sounds, and alerts to create distraction-free work times. This is helpful if you’re giving a presentation or trying to focus on a paper, you can use Focus Assist to block interruptions or distractions.
While Quiet Hours also helped users by providing no interruptions when the feature was turned on, it also lacked in-depth management options of who or what could break through the silence.