I believe both DAG currencies - IOTA and Byteball have great future ahead. Specifically for IOTA - Internet of things is picking up and number of connected devices would go into billions - this is one of the fastest growing markets also for company where I work. Due to number of devices connected and number of transactions that would need to be processed, the traditional blockchain based currencies are not suitable for this type of application, therefore IOTA, specifically designed for IoT transactions would be growing together with this market. It does not replace the blockchain currencies but it acts as supplementation to these blockchain networks.