I agree with both of you actually, app is great but I don't don't like Material when I see it usually unless it's skinned well enough to not instantly tell it's Material. Something about that default theme...

People with limited mouse dexterity. People who hate mice. If you don't browse with the keyboard you don't see the focus state move anyway, so leave it on for people who need it.

> Who browses with a keyboard? only him.

Many accessibility systems work by emulating keyboard movements.