They render in color for me. Those characters have 2 ways they can be rendered and the default varies. You can use the U+FE0F Variation Selector-16 to force the

They render in color for me. Those characters have 2 ways they can be rendered and the default varies. You can use the U+FE0F Variation Selector-16 to force them to show as emojis or U+FE0E Variation Selector-15 to show them as normal paths. Though color fonts aren't restricted to emojis, they can be used for any characters, they just aren't very common.