One way of thinking about neutral color tones is that they fall in between more distinct hues on the color spectrum, making them difficult to define. Another is that they tend to be more organic, mimicking some of the lighter and more muted shades of nature, like those of stone, water, and wood.
Because of their more subtle visual profile, neutral tones are considered calming and restful. They're also less likely to clash with more pronounced tints, which makes them good for unifying spaces with bolder colors or splashy patterns, and well suited for supporting visually striking art.
As peaceful, calming, and naturally influenced elements continue to come to the fore of design, neutral tones like off-whites, tans, taupes, and grays will be increasingly popular, including many hues influenced by or infused with stronger, more eye-catching colors.