This is maybe not as comforting as you think it sounds. 1.5B is 1% of the budget that you describe below, which is non-trivial -- that's make or break money. I'm guessing it exceeds the total annual contribution of several member states (I tried to find the actual budget, but talk about incomprehensible documents  -- what's an "own resource"? What's with the obsession with sugar?). To that end it seems like fines like this are a critical part of the EU's budget.
> If you sum up all the fines collected by continent
I'm wondering if you have a reference for that -- I can't really find anything definitive and it would be interesting as a data point.
47% subsidies for farmers, 30% regional support subsidies (e.g. they might co-found an R&D project in an outermost region in a country):
So mostly subsidies. If there's a deficit, they can cut the regional subsidies which I believe are mostly individual projects with relatively short timespans.
The farming subsidy is more like social security, I think you'd have riots in France if you cut that significantly. Which is sad.