Optical Built-in Viewfinder
Using a viewfinder during a street photography shoot allows the photographer to stabilize the camera and reduce the camera shake since it is closer to the body. Besides, it comes handy where LCD screens are very hard to read under bright sunlight. Manual Focus Mode
You can use the manual focus mode of your camera to Zone Focus which is a popular technique used in street photography. Live-view
Live view lets you take photos without using the viewfinder which makes you less obstrusive and this works very well during street photography where you don't want to get people's attention. Image Stabilization
Image stabilization reduces the effects of camera shake at long exposures and long focal lengths in street photography thus ensuring sharper photos. Fast Lens at Wide: f2.00
Wideangle is used more common then the tele angle in street photography. A larger aperture will give you extra shutter speed without boosting the ISO in order to reduce blur in low light conditions which is a common scene in street photography. 28 mm - Good Wide Angle Coverage
Having a good wide angle coverage becomes very important in street photography. RAW shooting capability
RAW files contains much more color information compared to JPEGs, and gives you more room for post processing without significant quality loss. They provide wider dynamic range and option to recover shadow and highlight clipping to some degree. Small Body
Small body of Fujifilm X20 will get less attention from the people in streets and give you an amateur look, which is indeed an advantage for street photography.
Small 2/3" (8.8 x 6.6 mm) sensor
An articulated screen gives you the flexibility to shoot in non traditional positions such as waist level, which helps you to be more creative and unobtrusive in the streets.