this case is overstated


it's only going to be the 'base case'/'cooperative case' that will become indistinguishable, e.g. Lightning channel opening transactions and cooperatively closed channels, because Schnorr "additivity" (which is not a real word ) makes such transactions appear the same as a regular [1 (or more) inputs -> 2 outputs] tx, because there is only 1 aggregated signature (because additive signatures, despite 2 parties signing the tx). Currently, spending outputs from that kind of transactions reveals it to be a 2 of 2 multisig that had alternate script paths, not so with the same script using Taproot/schnorr.

But ,uncooperative closes are still distinguishable from the regular [1+ in -> 2 out] transactions, because of the atypical script they use will (necessarily) be revealed if they are broadcast/confirmed in a block. I know, uncooperative channel closures are not common, but they will still sometimes happen when using Taproot/schnorr based channels/contracts.

And so, all other atypical scripts will still be distinguishable from regular transactions too. It's just nice that the construction of many contracts involve using the [1+ in -> 2 out] regular pattern as the base case.

Possibly another stupid question from me here, but can the Lightning Network then be leveraged as a use case for tumbling/mixing/hiding our UTXOs after the upgrade?