None of degrees can guarantee you anything. Get both of degrees, CSS and ACCA, still you'd find a person totally illiterate but earning even more than you.

Things that are important:
1.Luck (your "Rizq" finds you as your death finds you)
2. Ambition (you get what you search for)

So equip yourself with a degree that matches your expertise. But never take them as a source of money. If you wanna earn money, open up a bakery and retail outlet, school or academy is better option, stock exchange is risky but gives high profits. Else getting. rich by night has no way but illegal, I'd not prefer that, because you'll get what you'll have to get, why to go for illegal then.

Anyhow, I'd say, there is no match for CSS because ACCA is a side line degree, you can get that like if you're doing you Bachelor or Master. But CSS is not a degree, it's the exam to join Public Services. If you pass the exam, but don't join services, you'd lose your chance after 1 year.