Should `ggsave(bg)` for the background colour?

[teunbrand]

Spotted in the wild:
https://bsky.app/profile/alelazic.bsky.social/post/3m27g2zsstc2w

Arguably if a user sets the bg argument, they'd want that as the background colour.
In turn, that should maybe override a default theme(plot.blackground) setting.

[thomasp85]

My gut reaction is that we would do the user a disservice by blurring the line between theme and graphics device settings

[teunbrand]

I accept this gut feeling