We play so few internationals that every one is important, even friendlies against less than glamorous opponents, because they give us the chance to build combinations and get used to the tactical approach. Especially with the new coach.
Nelsen got away with it but I think that he helped establish this precedent, now the worry is that with more of our best players playing at a decent level in Europe it's not actually going to benefit the team because they'll all withdraw from friendlies and OFC qualifiers to help their Euro careers. Then what? If we do make intercontinental playoffs or the Confeds Cup they're all magically available again, but not used to the coach and teammates? Fuck that, if you want to play in the World Cup you damn well better commit to helping the team get there, which means playing every game that builds to that if you aren't actually injured.
Also, regarding the comparison to Nelsen, no one in the current squad makes as much of a difference individually to the team as Nelsen did when he was there, which is also part of why the response to him doing it was more muted.
You could also argue that with so few games being played is it even worth playing until absolutely necessary? There's only so much gelling you can do playing 1/3 the games of other countries.