First and foremost question is, do we really need one ? No, we don't need a soft release button. We have so many things in life we don't actually need. But hey, we all need to treat ourselves something nice once in a while.
Komaru Soft Release:
I use a soft shutter release button, as a matter of fact I'm so used to having one on my Leica that I would feel naked without it. Truth is, it's not so much about the look, but more on its functionality. Surprise, surprise !
A soft release button raises the shutter by a little, this additional height serves like a grounding point, a point that actually helps me to navigate the camera without looking at it. It's actually quite useful if you plan to hold the camera in a less conventional way.
I do zone focusing, it frees me from looking through the viewfinder. Physically speaking, zone focus is more of a wrist workout rather than using both your hands to handle the camera. Having this little button helps you, even a tiny bit, to hold the camera ever more securely.
And because of the way I hold the camera, I don't necessarily use my index finger to press the shutter. I use my thumb instead. So a soft release button with a large surface area feels right with my thumb resting on it.
All of us are unique in our own ways. And this is my story and my bias. A soft release button is a necessity for my camera setup. If you do zone focusing, you might actually enjoy using one.