This is like saying Z$ should make every fiat speculator or holder very nervous. Crypto is huge. You can be involved without coming anywhere near USDT.
You think the shockwave of the tether collapse will leave any crypto unaffected? What if some trading platforms fold?
Unless they are exposed to USDT, why would they fold? They are trading Crypto against USDT (as a token). If USDT folds, its their customers that are going to hold the bag. But many exchanges have USDC too (and maybe their own USD pair); so users should be aware.