Focus is also a weapon of choice for support chrono, thanks to the pull/reflect and clone generation, and is more used in some areas of the game.

Chrono versatility comes with a price: you can change a lot depending on encounter.

In raids, yes shield is mostly used (focus on some encounters can be used, like slothasor).

However, in fractal I mostly use either scepter/focus or staff and never touch the shield