The 1st picture doesn’t look like dissimilar materials to me.
The ACQ example, I think you mean to say aluminum flashing. I don’t see many alumimum nails for deck construction.
Another common example in houses is copper supply pipe supported by steel rods, metal dryer ducts touching copper pipes, etc.
Thanks, I changed the pic. As far as aluminum nails in ACQ lumber goes, I imagine someone’s gotta be doing it because I’ve read warnings about it everywhere.