You only use motion matching if you have a motion capture studio.
The reason why Ubisoft is developing this is because they want to insert raw motion capture data into game, because:
1: They have the motion capture devices required.
2: Motion capture cleanup costs time + money.
3: Animation state machines aren’t flexible.
So basically animators are implementing animation quick without the need for a dedicated programmer. All they need are some basic functions to look up frames in anim curves imported directly from MoCap data, later on combined with IK rigs for real-time adjustments.
In this case the state machine is just a mark saying “when” animation jumps from one frame to another, more like a state tree. There’s no animation clip per state.
Everything is one BIG animation playing all at once.
Fast, cheap and simple to do. Animators happy, bosses saving money also happy.