Is there a Dutch thread on this subject? Because I read a little bit on the dutch tax system, from what I understand, it's pretty relaxed 
you may check local boards 
good for you if your tax system is a bit relax on crypto profits, most 1st world countries have a serious law on taxation when it comes to crypto market because they notice a large number of people getting a good wealth in the past years.
That said, I have heard whispers that they are going to change and adapt this in the near future, but whether that happens or not is something these.