“Europese most important rocket test” is clickbait-y in my opinion. It was the first hop up test. Nowhere near “the most important”.

maybe I missed it in the article - why was there a piece of cheese?

edit - immediately saw the reason after posting this comment

Strapping the cheese to the rocket “was purely for fun, but in the end, it allowed us to discover some limits to our design – notably for roll control,” Marciacq said.