In standard line charts (e.g. line chart), it is now possible to define the colour of a data label based on a measure. However, that measure seems to be only evaluated once, rather dynamically based on the row context. This implementation makes it impossible to use colouring to show/hide data labels in the chart based on data conditions.
For example, you might wish to make data lables white for every case except the last date on the chart, but this won't work since the colour measure is only evaluated once.