The problem lies in the opacity of the Tether emission process. Because of centralized nature of its release, members of the crypto community are doubting if Tether has a reserve fund.  Over the years, different government agencies have launched investigations into the Tether organization. The story of Tether continues and is unlikely to be resolved in the near future. However, people still use it as it is one of the most convenient stable coin so they have to trust it.