Bioness' system is not something I would implant in my office normally, but you could. It's percutaneous, but implanted, but not in a deep cavity, so as long as you've got decent sterility/some simple surgical equipment/etc, you could.
Payment wise, you will get paid something in your clinic as per above, but the lead/system itself I think is in the $3-4k range depending on your volume, so it works financially in the outpatient ASC vs hospital setting. Now if you're making an incision and billing for the 64575 code instead of the 64555, you're a baller and making bank, but only in the ASC/hospital setting.
For time to implant, I have the most variability in case time with this system as the cases go great (20-30') or drag out (1 - 2h). It captures a smaller volume of tissue and the electrode field has an odd geometry to consider, so if you're trying to get sensory/motor capture throughout, you may struggle on some nerves. If you're good with an ultrasound and plan things out before, this isn't hard unless that patient's anatomy sucks. If you're not paying attention to detail, it'll always go great regardless, but not sure if the long term results will be that different than a fancy TENS patch.
Technically it is not very challenging, but more involved than the SPR system. Financially, the Stimwave system seemed best remunerated but more involved. I have not had exposure to Nalu though.