To butcher a common Shakespearean quote...
"An accessory by any other color would play just as fair"...
While people tend to color-coordinate accessories with their systems (if you have a White Wii, White Wiimote, White Nunchuck, ect... would you tend to go the White Wii Wheel) to maintain a color scheme OR to individualize sets, it's mostly a personal preference.
With my original Wii (which was white, as it was the only color at the time), I had a White Wiimote + Nunchuck. When I picked up the Wiimote Plus, I strayed away from the trend & went with Black for a change (& I got it bundled with a game). I picked up a Black Nunchuck for it to have a complimentary set for 2-player gaming. When I picked up The Legend of Zelda: Skyward Sword, I went with the bundle as well to get the Gold Wiimote Plus. While I wanted to get a Gold Nunchuck to go with it (in order to compliment it), that was a limited edition item & I wasn't willing to cough up the premium price that was being requested on the secondary markets. I practically retired the original White Wiimote (getting bumped down to Player 3. The Black set going to Player 2) & use the Nunchuck with the Gold Wiimote Plus. In this sense, I color-coordinated by player.
If I decide to purchase another Wiimote (whether for my Wii U OR for my original Wii that's now residing at my parents), I will try to color-coordinate when possible as it's just easier to do a mental inventory (Black Nunchuck goes with the Black Wiimote, the Blue Nunchuck goes with the Blue Wiimote & the Snozberry Nunchuck goes with the Snozberry Wiimote... whatever color a Snozberry is). It's mentally harder to pair stuff up that isn't the same color (like a Blue Nunchuck with a Pink Wiimote or a Pink Nunchuck with a Black Wiimote or a Black Nunchuck with a Blue Wiimote... damn my set symmetry here) as it just doesn't seem to "fit" together naturally... hence the perpetuation of color-coordination. When color choices are limited (like going with black or white to use with a blue Wiimote), you tend to more "free" (in an ironic sense) in the selection.
The point here (TL;DR) is that if you can can mentally deal with non-matching color sets (however you prefer to define them), go right ahead. Just don't be surprise if others get potentially confused or disoriented by this.
Hope this helps!