I wondered the same thing as I was looking to gather programming hardware. This summer there was one supplier on AliExpress that was selling the Mini-Pro for US $175 delivered price summer special, and it was very tempting. However, once I made a connection with ebay seller help2hear, I wound up purchasing a serial Hi-Pro from him. He says he has several available but not currently listed on ebay.
As far as whether the Mini-Pro will work or not, I am not sure. I bought my hearing aids from Phillip Rechister, ebay seller bidbybid. When I talked with him to order the ribbon cable adapter pills for the hearing aids, I mentioned that I was thinking about the Mini-Pro, and his comment was that the only wired devices that work with Siemens aids are the Hi-pro and Noah devices. I don’t know if that is true, but Phillip has been in the HA business for a lot of years. From what I have seen by reading on the forums and other places, the Mini-Pro might very well be a usable device. By the time I was ready to buy, the price had gone up to $234.00 and I paid $200 plus shipping for the serial Hi-Pro, so I decided not to risk the Chineese device. I see the price is down to $219.00 at the moment.
If you decide to take the risk, be sure to let us all know your results.
Oh, one other thought. The fitting software only recognizes the Hi-Pro and Noah devices plus their own proprietary wireless devices. The Mini-Pro would have to be recognized as a Hi-Pro to be seen by the fitting software.