That guy seems to be impossible to explain this. His argument is now reduced to the assertion that Bitcoin will fail because of paperwork businesses would have to fill out for exchange rate gains. I hope somebody would come here and explain it in detail whether it actually requires that much work and how often
Personally, I don't believe him but have no experience in this field to refute with competence...
No my argument is that bitcoin wont become a media of exchange because government enforces its monopoly on money with all its might.
You could just have said at the start without much beating about the bush that government would outright ban Bitcoin, and nobody would be arguing with you on that point. Though this has been discussed so many times here that you could hardly add anything new to the debate and that would be boring...