It will stop countries not playing to avoid damage to their coefficient, like Wales and Switzerland have done.
https://thesetpieces.com/world-football/beating-system-wales-planned-seeding-success-calculator/
So is this instead of Euro 2020 qualifying?
No, that would be too simple. Euro 2020 qualifying is set back until March 2019 and will end in November 2019. But the Nations League will a) decide the seedings for the Euro 2020 qualifiers and b) provide another route to the tournament, with four...