The mini is for those who are willing to spend the extra money on a grinder. Theres nothing wrong with less expensive grinders such as the lux, iberital, or rocky. Theres a few stepless adjustment grinders on the market, namely the mini and iberital, and some others.
In the end, its what floats your boat, Mercedes or Toyota. The price tag doesnt necessarily mean its better, just more expensive, and has different features.