For workflow purposes, it will be easier to think of the Erase Color as simply an alternate paint color. Using the erase color is not like removing your previous strokes, as it would be while using the Erase Tool in Photoshop or a similar image editing software. Rather, you are just painting on a different color. If your base was white, then it would be a good idea to use white as your erase color.
While in the Mesh Paint Mode panel, you can also hit the Swap Button to swap the Paint and Erase colors. This is especially handy when you need to quickly jump back and forth between a pair of colors, or do a fast touch-up on a misplaced brush stroke.
Keep in mind that the Color Picker has a variety of means to aid in the quick selection of colors, including saving color swatches and setting up color themes. Please see the Color Picker documentation for details.