These wires are ideal for people who are going to make a lot of crosses with one pollen parent.
EX: If you have a red wire on a plant you know exactly what plant it came from because you only use red wires for that one plants pollen. Plus, they are not as visible as the tags. Also, if you run out of wire options you can put two or more together. So your red and green wires twisted together represent another pollen parent.
They are easy to use and they can be reused next year.