It depends on the model, some universities are easy to get in but have weed-out classes, some are hard to get in but comparatively easy to finish, and some are both hard to get in and hard to finish.
Discrete maths back in my days was one of those almost universal weed-out classes which got rid of people with limited abstract thinking ability who weren't willing or able to get over that with hard work. Very heavy correlation between how well you did in that class and core CS subjects.
There is no single large market in Europe, everything is fractured by language and different cultures in each country. Monetizing it is also difficult.
Yes… but from my point of view, if there is an alternative solution without those restrictions, I’ll go with that. I’d only consider a solution with such restrictions if its other advantages were so compelling as to overcome that (and even then, if one has to ask legal, it isn’t guaranteed they’ll say “yes”)