About thether: USA regulations end up helping them - american concorrents, possibly more transparent, end up swallowed by regulation.
By increasing the reach of USD and buying Treasuries to back their tokens, thether ends up helping the USA government.
And they solve some important use cases, such as international merchants and industrial-scale smugglers who need USD outside of normie banking. Even a BTC maximalist should understand that BTC is not the best coin for all immediate, current, use cases.