it's fine as is....could be a different shade of white however, if you care to do the selection and then the work. Adding a backsplash would make a more change element, for any effort you put into it...... rather than different paint. With a painted surface you can add small plate rack and display things along the backsplash, which can be nice. I'm seeing the topiaries and iron piece...so you can do the "pretty it up" with things hung there, taking from your style so far.

I have a friend who put up a beadboard backsplash, painted white to match the cabinetry, while deciding on a "permanent" one. I don't think it's going away any time soon because it looks very good. You can still hang stuff on it.