When it comes to getting the USD back, sure. Even if the machine only mines 10 BTC in it's lifetime it is likely a matter of time. Just hold and you will most likely at some point see ROI in USD. But that is beside the point if the initial investment was in BTC.
If you sell a box for 50 BTC that produces 20 BTC over its lifetime (while eating energy and making noise), it does not sound like a product you can build your business around. Yet that is exactly what we have pre-ordered now that delays are a reality.
All true, but also worth noting that the MPP was expressly calculated in BTC from day 1, without regard to form of payment. You could pay in BTC or by bank wire in USD. Either way, the MPP was the exact same ROI pledge. In the case of USD payments, it was BTC per the BTC/USD MtGox exchange rate on the day of purchase,*** in other words, the exact same. This was an important consideration for USD customers and is a core feature of the Program. Two forms of payment, but only 1 MPP.
*** They later switched to another exchange's rate, I forget which one.