It started this way, actually. But in the day-to-day use it ends up being an embellishment, because there would typically be a string of read/writes that fall on the first pixel of every band so they'll highlight the boundaries, for free.

Different color could be a little bit distracting for minimal design, maybe there could be gaps between bands. The bands are independent with each other, a 999M 999K 999B band look like a continuous band but it should be 3 separate bars.

This is just pure nick picking, your current design probably suit your need already.