Euro or dollar are equivalent to the gold reserves

NO

Bitcoin, Litecoin, or Steemdollar do not have a worth, there are just worth anyting beacause people believe that this virtual money is worth anyting.

Currently STEEM is priced at a little bit of 4 USD. So, I think: well if I buy that STEEM and then I upvote in Steemit, after seven days I will get, by upvoting some posts, at least 0.01 USD. That will be in my pocket in just one day. Multiply that cent for 365 days and you get 3.65 USD.

So, I paid around 4.15 USD to get, in a year, 3.65 USD. That day in the future, I will have 3.65 USD in my pocket. Plus the STEEM token, which will probably be priced higher.

Also, the 3.65 USD worth of STEEM could be added to the STEEM POWER, so every new upvote could bring me more that 0.01 USD after the week.

Find me one single stock which offers you that kind of return on investment :) Don't make the same for fiat currencies, as there is no ROI in them -at least the same way-.