Is it possible to leverage trades within the US? Which sites have this option? Do US traders need a VPN? Is this safe? Thanks!
I think that most US based traders simply get a VPN, as you say, and trade on either Bitmex or Deribit because of the fact that they have the most liquidity and are still the overwhelming dominant forces in this area. Spot exchanges can't really compete with the product that they offer, especially Bitmex.
Of course you are running the risk of getting banned, or whatnot. It is clearly against their Terms and conditions which means that they could ask for KYC, suspend your account, blah blah.
In reality though I haven't seen anyone actually gotten this treatment. If you think about it, the platform itself has really no incentive to enforce the rules, and they can't really determine the true country of origin anyhow without any verification.