1a. Mining is absolutely inefficient as an individual and barely economical if you're Bitmain. That's a complete red-herring.

1b. Effectively nobody accepts bitcoin. It's something like 3 major merchants and around a couple thousand total, world-wide. So yes, you will be buying BTC for real money and exchanging it for real money on the other side. Pretending we live in a land of hyperbitcoinization isn't helpful.

Further, you incur huge forex risk in between the time it takes to buy, transfer and re-sell. Do it at the wrong time and you could lose tens of percentage points. The parent post understates the cost as a result.

2. Drugs.