Goes back to what I said before, depends on where you'll be traveling.

Pointless to get a Green Pass if your main travel is on routes that have no green cars.

Again on luggage space, there is no more or no less luggage space on a green car vs a ordinary car, the luggage compartments are the same exact size.

Finally its pointless getting a JR pass if you don't need a JR Pass (I've seen many people talk about getting a JR pass when in fact they were just flushing yen down the drain because they didn't need it), so it depends not only where you're traveling but how much traveling and the time interval.