If KYC is in effect then Alice and Bobs addresses are known to regulators. Even if the transaction is "untraceable" we can know that Alice's wallet now has less coin and Bob's has increased coin of the same value, effectively nullifying the untraceable attribute from the transaction.
not sure i follow because that is how btc works right now. most merchants use 3rd party btc services like bitpay etc which is aml/kyc compliant.
one reason they use these 3rd party services is because of btc's slow transaction confirmation times and assurance against double spends etc.
DASH solves those issues with instantsend technology.
also, alice and bob (p2p) are not required to comply with aml/kyc laws. however most business you want to do business with are required. it does not matter if you use btc or dash or some other crypto that does not even have a official gui, ariel.
if you buy something from dell or overstock etc they know who you are as you have to give them your name and address to ship to. true they know the crypto address where your funds came from but unlike btc they can not conect your dash address to all your previous transactions.