Actually..... Kelvin is the unit for color temperature.
What matters to plants is the spectral distribution, which can not be expressed in a single number. It is a curve with peaks in various wave lengths.
Kelvin, in turn, is just a number given by the manufacturer to give us an idea of the expected looks of the bulbs. Sometimes, these numbers coincide with a blue or red hue, but sometimes they don't. Especially for plant grow bulbs, it's just a rather random number. One manufacturer might say one bulb is 2800K, another might label another one with 18000K, and none of that makes much sense or matters to plants.
Pink/purple plant grow bulbs have their peaks in the red and blue parts of the spectrum which is supposed to be optimal for plants. Human eyes are more sensitive in the yellow/green part, so the plant grow bulbs look a bit weird and often dimmer as their "regular" counterparts of the same wattage.
Keep in mind that plants need a certain amount/intensity of light to grow (photosynthesize), and as long as that is given, they are pretty adaptable. If your lighting situation is borderline, choosing some plant grow bulbs should be advantageous.
If the overall light intensity is sufficient, I'd say go by what you like. Some like warmer tones, some like greenish light, others prefer crisp white light. Mixing bulbs can be beneficial for an overall balanced impression. For example, I mix neutral-ish 6500K bulbs with bluish-white 10000K bulbs and pink plant grow bulbs. I would not like one of them on their own, but as a result of the mix the tanks look nice to me.