Thinking about it more it reduces track time so could reduce amount of engines which is a big cost. but surly they'll just run engines at a higher rate, unless the rules limit engines even more.
Also with lack of testing FPs are the testing. Testing bans is making it harder and harder to solve bad cars.
This is directly what the teams have said. Less time running means less wear and tear, less parts being used. With the engine being expensive it could end up meaning a couple less engines throughout they year which isn't insignificant.
I think it was Force India saying FP1 helps them make some money, from the way it was said I presume it means a lot of the younger test drivers are pay drivers that effectively pay a big fee for their chance to impress and get a drive.
There is also advertising, more time on camera = more potential for income. On top of that if lots of people completely give up on going to friday sessions because for one practice it isn't worth the trip then again there is potential for less money there.
I guess there is an argument to be made that with less testing time you might have more races where one or both drivers in a team can't get their car setup right and you have a little more variability. A merc which just doesn't handle right and has a difficult race.
More running is better for the fans, it's a spectator sport. Maybe, just maybe rather than cutting costs, Bernie and the people in charge can take a less insane portion of the profits and filter the money down to the teams better.....
More money for the teams, closer competition from the poorer teams, can't have that when Bernie can just pocket as much as possible.