It's interesting to see that the internatl. SIM card sellers in Europe are starting to get in panic and are lowering their prices.
This Dutch SIM card is actually a KeepGo SIM which is sold more expensively in the rest of the world:
https://www.keepgo.com/pages/europe_sim_card
Some considerations:
1) 1GB at €25 is expensive when you consider that Vodafone in the Netherlands sells 1GB EU data on regular prepaid at €10 valid for 1 month.
2) The major difference is that Keepgo/wereldwijdwifi has a 1 year validity for the data credit. So it can be used for lower volumes and at several occations/trips.
3.) But in about 8 months (that's July 2017) all roaming surcharges will be banned in the EU (within a possible FUP). This will dry up the whole EU market for these products. They can still try to sell them overseas, but I don't think that users will be so stupid.
So what's the use in spending in a long-term solution, when the rules are going to be changed (again) soon?