While it's better than "meaningless" friendlies I'm afraid I can't raise any enthusiasm for it.
Essentially it's UEFA exerting control over the games outside qualifiers to limit the "gaming" of the rankings systems in friendlies by making sides play four games against teams at a similar level home and away.
Unfortunately the 3 team group approach makes the competition a little unbalanced in that each round of fixture one side will play twice while the other play once.
God forbid that anyone would "game" the new system by picking a reserve team for a non-competitive friendly before playing a Nations League game!