Please I may not be the only lame man here I've longing to know why People typically use bitcoin mixers to mask any previous "questionable" transactions from the bitcoin that they are likely cashing out in their real name. Now let me know about purpose of mixing bitcoins.
its for hiding your transactions
but keep in mind that dosen't 100% mean it's for criminals only
there's much OPPRESSION in many countries, and some feel like they HAVE to hide their money

ive never used one, as i have never NEEDED too, but i understand others do
Of course it wasn't design for criminals, but the thing is that they take advantage of this mixing services around and that's why it has given bad reputation in crypto in general.
I personally used mixing services to hide myself from everyone, and enhance my security and privacy in this crypto sphere. However, for those who are really paranoid about their privacy, its better to move to privacy coins such as Monero and not used a tumber services, in my opinion.