Why might dark-light-choose() not work?

Thank you so much, Kris. You saved me! It works perfectly :tada:

I’ve been playing around with it and the only thing I don’t understand is why variable interpolation is required with color values. For example, this doesn’t work without interpolation:

$ins: #7f7e7e;
:root {
  --custom-ins: $ins;
}

But this does:

$ins: #7f7e7e;
:root {
  --custom-ins: #{$ins};
}

Both versions work if $ins is assigned a variable (for example: $ins: $dark-theme-ins ).

What am I missing?