We have about the same differences between commercial banking and investment banking, and there are many economists arguing about the need to separate (or unite) these 2 activities. We shall have the same discussion with cryptos exchanges.
Many legislators around the world are talking about regulating exchanges, this is what they should talk about first.
I don't get the point of your forum thread.
All crypto exchanges are regulated(or they should be). It doesn't matter if they offer just "crypto to fiat and vice versa" financial services or crypto trading/leverage/margin trading financial services. The authorities might distinguish them, but they are both regulated. In both types of crypto exchanges the users have to submit KYC verification, just like in all fiat financial services.
It doesn't matter if you are using a commercial or an investment bank, in both cases you have to submit KYC verification.
Separating the exchanges into different categories isn't our job. I guess that they are already separated by the regulators.