Because C-CEX still haven't successfully integrated the HEAT wallet to their exchange. We're providing all required assistance and even full NXT backwards compatibility, but we can't access their servers to complete integration. To my understanding it's hard work to host trading and constant integration changes for 200 cryptocurrencies, thus likely the lack of resources is unfortunately preventing them from completing this.

Using escrow for ICO has two sides - the flipside has obviously been the most prominent case with HEAT. Direct investors have been free to move their tokens since January.