"Roughly, you pay taxes (1.3%) over whatever crypto you had on the first of January of 2018."
Uhm, no. You're doing taxes over 2017. So 1st of Jan 2017 is 1 value (convert that to euro's at the rate of that date) and 31st of Dec 2017 is 1 value (convert that to EUR at the rate of 31-12-2017).
There, you're done with how things are done in BOX3 (vermogensbelasting).
However, in your video you are talking about income taxes. If you are considering Steem to be income into BOX1 (income) you are talking about a whole different ballgame. It will be pretty difficult to find good advice on that subject, exactly because of the questions you are asking.
So I would suggest (but no advice, no responsability, no liability accepted, etc) just put em in BOX3.
Man if its 1.3% than might be no problem but what if the taxes raised to 30% of your earning than it might not be the good idea for the people.
You are correct. I edited the post. And yes, it's the income tax that is the biggest puzzle. That's why I also suggest putting some (worst case) money aside.