It's interesting to see that Turkey has come out with very generic guidelines. They have basically stopped anyone doing anything into cryptos and have even stopped everyone to create any business models around cryptocurrencies but this would hamper the growth of their blockchain industry too. Primarily also destroyed it as a medium of payment even in International Transactions. But here is a very interesting loophole at least for the investors/ traders that I have found:
We can't really know the main intention behind it, this is just a law that was put in place and there is no reasoning given. However as far as I know there was a big problem with the gambling using crpto as well, that seemed like a story a year ago or so, which is why I do not know if it is still a problem or not. But, I do assume that it could be a really big deal or not that caused this.
If Turkey has a lot of people who pay with crypto and deposit to casinos and gamble with it, and the government specifically banned gambling, that means people are using crypto to find loops around the law and use it as a means of exchange.
Not like we live in a world where we pay for our dinner with crypto, so it wasn't really a big means of exchange anyway, where do you really spend your crypto? And this law prohibits third parties to be middleman for crypto means of exchange as well, you are still free to do it directly from person to person as long as you do not use another company in between, doesn't sound like a big deal.
I think a random guess which I can make after the US Sanctions on Turkey and the long-time troubles with the Turkish Lira and its devaluation can be a problem. If people's faith over their fiat will reduce they will start to use another form of currencies especially cryptocurrencies which would lead to lower demand of their currency and further aggravating the problem. Basically, they are at very early stages of becoming another Zimbabwe and they definitely don't want to become one.