I think the blue gives it an added layer of depth and separation. It's also more aesthetically pleasing that way.
Another thing you should consider is how color flows from one page to the next. I would keep it as consistent as possible and make any change in color mean something. For example if you want to show a scene change then shifting the color pallet will help visually indicate that. You can use gray scale for flashback sequences or dreams. Even if you want to just change it up, I'd wait until chapter breaks so it doesn't seem so jarring.
For example, on my strip The Working Stiff, every time I have a new arc I slightly shift the pallet and keep it consistent for all the gags that belong in that grouping. This way even though it's not obvious that certain strips belong together, visually your brain relates them.