That's quite a big stick though, isn't it? "Declare who are your champions, runners up etc., or we won't let anyone from your association into the next CL".
Some of the CL revenue paid to clubs depends on who were domestic champions/runners up/3rd/4th too. (Market pool- https://www.uefa.com/insideuefa/stakeholders/clubs/news/newsid=2616265.html)