No one needs stablecoins. Stablecoins only invite speculators who want to reduce their exposure quickly and efficiently while hiding from the tax man. This is bad for a market that is already being manipulated by big money whales.
Not to mention that stablecoins are also used to artificially pump up the market when there is no real growth.
An investor has no need for a stablecoin. He/she has done their research and believes that crypto will be a lucrative investment and/or has a real world use.