All fiat currencies can be speculative assets. Why bitcoin can't? There is a whole financial market called Forex, which is based on fiat currency trading pairs such as USD/EUR.
The answer is given directly in the post. The ratio of the real/financial markets shows the perception of an asset as transactional/speculative. To a certain extent, all assets, including cash, are involved in speculations. However, if in 90% of transactions an asset is exchanged for real goods and in 10% for other assets, this looks like a medium of exchange or a currency. In the opposite situation, the asset looks more like a speculative non-cash asset that cannot be considered a currency.
The reward distribution is basically a fee paid for a service (securing the network, through mining). The incentive will last only a few decades, which will also generated new coins and properly distribute them alogn the years.
Yeah, it helps make the system secure and doesn’t help reach the initial goals for which the system was created. That’s what I’m saying.