At the current conversion rate, 50-euro, that's over $61USD. I can relate to that easier. Personally, I do feel that is too expensive. A few years ago, at CalStates and BAC yoyo contests, the registration fee was quite high(closer to $100) and yet we still had big numbers turn out for competition. For yoyo, considering the numbers, we have to have preliminary rounds, of which, well the top 20 would move forward, and the top 5 seeds, for 25 in the finals. For many, it's $100 for your 1 minute of attempt.
20-Euro comes to about $25USD. That seems an ideal fee. Even for here in the USA for the smaller contests. Plus, the required NYYA fee(once a year only), it's still reasonable.