Steem or any other crypto are not likely to be used as a currency any time soon. How can you use something that fluctuates 10% on a daily basis? That isn't a currency, it's an investment. The coins that have use cases as currencies are stable coins. Perhaps eventually some coin can be used as a currency but not until the volatility drops significantly. And this doesn't even take into account the tax issues trying to use one as a currency... as they are written now in most places, it makes it very difficult if not impossible to use one as a widely adopted currency. For now, it is best not to focus on the currency aspects, but instead focus on the utility/speculation side.