It's interesting to note that the company that developed the chip (Gigadevice) initially got big by copying microcontrollers by ST microelectronics. This went as far as copying the entire product portfolio including naming scheme and marketing strategy. (Personally I find this absolutely appalling)
I guess not having to develop a software toolchain for their devices provided a huge benefit for them. Now that they have a device that cannot rely on external tools, things look a bit more difficult...