I wish Google was going to continue investing in this. I think desktop applications are passe now that mobile everything is here, but the reality is that desktops are still significantly more powerful with regard to serious editing compared to even a Surface Pro. I use the Color Efex and Silver Efex components quite a bit for landscape and black and white editing.
This is a before and after Color Efex photo taken with the K3 and DA 15 limited.
Pre-editing.
After Color Efex Pro (used a digital GND, detail enhancer, and contrast)
Silver Efex Pro is nice too...