So, Mixers provide service of shuffling bitcoins or provide addresses loaded with bitcoins along with private keys. In short, they provide service so to create anonymity between sender's and receiver's address so that no one can trace the transaction.
My question is why not use Exchanges? When we deposit funds on exchange, bitcoins get deposited on exchange's cold wallet. But when we withdraw funds, withdraw gets processed from exchange's hot wallet. So in short, it is very easy to do anonymous transfer by depositing funds on exchange and withdrawing to other addresses. Why to pay 1-3% fees on Mixers when it could be done for much less on Exchanges. Exchanges like Binance charge just 0.0005 BTC to process withdrawals.
Both exchange and mixers are essentially helpful and has its purpose, choosing it will vary according to its purpose and where you're gonna use it, if you're planning of investing, trading, or you want to have a high-powered and reliable security, i think uou should use mixers because it will actually break.the link of your address both the reciever and the sender making it untraceable together with making your privacy key private as it said. , if your gonna have a simple life in crypto you can use exchange instead.