It shuts down because it is not meant to work in standalone mode for a long period, which is meaningless. Still I had to mention that.
In through-line mode it can work for hours without a prob.
Calibration, I was just informed that tomorrow they will release a new firmware update that will allow it.
It is innovative because it is the first time I see such an affordable tester offering all those features and I know a thing on this subject

Only a good multimeter can cost more than this tool.
Everything has to do with support and not only hardware. Surely a Chinese factory can make it less affordable if they produce thousands of these. But what about the software? Will be usable and above all, will be updated regularly. I see the folks at PassMark trying hard to make this work and I liked their work so far. Many of the issues that I found can be solved with firmware updates and I am expecting to see the final result.