With mixers it's usually* the other way around.

They do an excellent job at obfuscating the origin of bitcoins through several coinjoins, but this comes at the cost of "risk assessment programs" blacklisting them.

Same deal with Wasabi coordinators.

Exchanges really really do not want you to send them funds from a mixer, they don't like those funds because it gives them legal headaches and regulatory problems. If they could accept them, they would, as it's good for business. But they can't, so that's why they freeze them all the time.

*There is one family of mixers that do give you "good" coins all the time, by giving you coins that investors sell to them. They are listed here.

Here is my take on all of this.

If you hold a soft money (fiat, diluted gold/silver, shaved coins) and a hard money (pure gold, bitcoin), you will want to keep the hard money as a store of value and you will want to spend away the soft money as a means of exchange.

Merely using fiat as a means of exchange doesn't really give it any value. If the mere action of passing a buck around gave it any value, we would just sit in a circle jerk and pass around a $1 bill until it gains more value.

Value is based on demand and supply. Changing hands does not increase the value of anything. If so, my ex wife would be worth millions.

People will stash away hard money, and spend away soft money. It's simple logic. Fiat will keep being used as a means of exchange until we run out of idiots to accept it from us.

Bitcoin will only gain in price as more of use store our value into it, and save it away in cold storage. Not being used as a means of exchange is only a testament to the value of bitcoin. It's not detrimental to bitcoin.

If useage as a means of exchange was required to remain valuable, gold and bitcoin would drop in price as fiat would gain value. The other way around is happening.

I think that any exchange, in fact, would be happy for the volumes and money flowing - however, the reality is harsher than that 
If you are a CEX - you abide, of course.

The topic about Gresham's law has been discussed more than 1000 times on the forum. Just search for old forum threads instead of posting another one.
Saving BTC so much that the value of BTC is lost? What does that supposed to mean? If the value of BTC is lost, saving BTC becomes pointless. The people are saving a currency or an asset because the future value/price of that currency/asset would be higher than the current price. If there's an expectation that the future price/value would be lower than the current price/value, nobody would start saving that particular currency/asset.