What is the point of the HYBRID OVF?

The X100/Xpro1 has three viewfinders - optical, electronic viewfinder, and rear LCD. Each system has it's differing uses - I'll really only explain optical for brevity..

Unless you habitually distrust your camera's AF (get to know how it works if you do) the OVF is ideal for simple point and shoot operation ... the archetypal 'street shooter' mode. You can see objects or people entering/leaving the basic frame guideline and judge the moment of best composition.

EVF & LCD do not offer this facility - being more or less 100% live-view monitors with observable or 'continuous' AF focus feedback ... better suited to critical framing/judging areas of focus, etc.

That's the point of an OVF!