Most of the engineers will probably select PSoC6 for applications, where it will benefit from its dual core design. This is a special feature. More technical information can be found here: PSoC® 6 Dual-Core CPU System Design
Also, PSoC6 will be the first with an AES module, which will offload from the CPU; new 40 nm manufacturing process, lowering the power leakage (and many more features!).
It is hard to list all the applications, the limit is only your imagination. Its not usually meaningful to buy a product and try to find a usage for it. The exact opposite is the way - try to solve a specific problem and find the most suitable components (and take cost, development time, ... into account) for your solution.