Mixers have a bad reputation especially to the feds which I am sure you know about different mixers being seized by the feds. In my opinion, mixers was not created to be used for shady stuff like money laundering for example because it is the person that is using the mixers do shady stuff. It is the same as the knife which is used in kitchen but there are people who use it to kill people and for mixer is what I explained that it's entirely depends on the person who use it either for shady activity or for privacy.
It's primarily because mixers are often labeled by governments as "money laundering tools". Especially the US government. Even if you're not a criminal, using a mixer alone will raise suspicion by the authorities. Luckily for Americans, the Trump administration has promised to go easy on crypto. I'm sure the US will change its stance towards mixers soon.
To be on the safe side, use a non-custodial mixer (decentralized) instead of a centralized mixing service. Most people claim to have "nothing to hide", so they won't give a damn about their privacy. They're fine using Bitcoin just the way it is. I'd say mixers are for the true paranoid. For even stronger privacy, converting your BTC to XMR remains the best choice. Let's hope other countries open their doors to Bitcoin mixers and other privacy techniques for the benefit of all. Just my two sats.
