i am czech. basically whole europe is part of bologna system, which makes it easy to standardize and compare schools between countries and do different stages in different places.

so basically you do 3 years for bachelor’s degree, then you do another 2 years for master’s degree. these 2 don’t need to be at the same school or even same country. if you are continuing within the same school, you may be accepted to master’s based on your grades. otherwise you go through some application process where grades may play a role. it is the same when you apply for phd position. so the grades may definitely affect you. it is true that once you are done with the school and have your diploma, your grades are not really the topic of the conversation, but before that happens, you may have a reason to care.

(medical and law schools are exceptions from this system).