It would be rather fun to see how many teams that actually do use their good players in scrimmage games. I guess we would be way down at 0.0... something percent.
Sadly I think you are wrong about this one. First the majority of theams reside way down in division V or lower in the mega nations. Most of these managers have no idea what they are doing and there are too many of them to help. If they are like a lot of noobs in Australia they constantly wreck the game shape of their players by playing them three games a wek thinking they are getting a benefit, winning, more training minutes (90 gotta be better than 48 right?) and more experience.
Then there are the times you are training three decent players so one has to play 48+ in the scrimmage to get his minutes.
Finally about twice a season in Australia we have some sort of scrimmage challenge. Usually during the all star week, the last week of the season, or less popular the first week of the new season. For example there was a scrimmage war between Australia and NZ where teams sent out their best in the scrimmage to do battle for their nation. There are also sometimes friends that like to scrim at these times. These matter.
As fas as anything Pini said, it is wrong. I support the Melbourne Tigers and I not only don't care if they won their scrimmages I don't even know if they did, who they played against or even if they had any. The exceptional case of a game against a team like the LA Lakers would hype up the team for sure but do we want to reward teams who can organise scrimmages against BCtooroo, Sharman Globetrooters and Venemous Scorpions?