it would,if you have your stash in bitcoins,there will be no sense in buying Monero or dash
and then paying the fees to transact,possibly lose on the exchange rate
and after all convert back?
there is also no 100% guarantee that your purchased coins cannot be traced to an exchange or exchanger you have been using
you will leave at least some fingerprints,so why not just use the mixer first place
but with Bitfury planning to introduce their new tracing system - http://cryptotimes.org/bitcoin/bitfury-exposed-millions-blockchain-users/
even bitcoin mixers might become obsolete soon