Since the new osu!update this recommendation is not anymore needed. So I guess we can remove it.Taiko Ranking Criteria wrote:
Custom Combo Color
Custom combo colours do not really matter to taiko as they will be overwritten in actual gameplay. The case is the same with combo numbering, but you may wish to use the numbering to mark out red/blue notes visually within edit mode (assuming no custom colours have been set), this would make modding for other people easier and could make mapping easier: