Synthetic yarn is somewhat maligned for being a cheap alternative to natural fibres. This is one of its' benefits, though. Cheaper than many natural products so it is more affordable. It often is hollow in nature so the meterage is usually better and it is more tolerant to chemical and physical processes than natural products, so colours are brighter and there are more effects that are achievable. It can be made to feel like the real thing too and people are less likely to suffer an allergic reaction to it.