It might rain during your camino, or it might not. You can't base whether or not you need waterproof boots on that unpredictable unknown.
Personally, I think boots - waterproof or otherwise - are unnecessary for hiking unless you are hiking in snow, or carrying a heavy pack through lots of water crossings. But for general, 3-season, light-load backpacking (i.e., the camino), boots (especially waterproof) are unnecessary.
If the weather is bad with lots of rain - you will get water in your boots at some point. If the weather is hot - you will sweat in your boots. You are more likely to get blisters wearing those wet, heavy boots, especially if they are waterproof and slow to dry.
Personally, I wear Asics gel trail runners or Keen Voyager (not waterproof) hiking shoes. I apply Body Glide (and sometimes a "fingerless glove" gel toe separator) and a single thin or medium sock layer. My feet get wet, even soaked, sometimes - but everything dries quickly and I never get blisters.
This is just my experience. I have been hiking all kinds of trails and roads, in all kinds of conditions, with all kinds of weight on my back. I started off years ago with heavy, waterproof boots and it was killer.