I am using and holding the majority of my portfolio in Tether as this serves as a cash position and it is the first choice to trade in cryptocurrency. It is minted (not mined) on many blockchains so you can choose the cheapest and fastest variant to your convenience. It works as a better version than dollar as it can be transacted faster and cheaper (esp. TRC variant is free) so the crypto community has been embracing it. It can be stored at many platforms for high APY (more than 10 %). There is no better option now which will have same adaptability and will be so widely used. The main issue with Tether is that it has never been audited so there is no guarantee that the amount minted is backed by the same amount of USD. Nevertheless the market is the main force behind the valuation and it seems the community has a faith in its value.