I think the traceability concerns are mostly handled since while it might be possible to infer an identity from an address that's sent to or from an exchange ac

I think the traceability concerns are mostly handled since while it might be possible to infer an identity from an address that's sent to or from an exchange account, it's a lot more murky once those coins are moved elsewhere. If you know that address ABC belongs to me, and you see I sent coins to address DEF (which is entirely offline and using a brainwallet), and later DEF sends coins to GHI, you're left with the task of proving that DEF and GHI belong to me, and weren't me paying someone else.