Good point on copper slip. I was using it as a generic term really. Pure metal based agents can indeed increase the chance of bimetallic seizing but most anti seize agents either metal or ceramic based have other chemical additives in them like graphite and molybdenum to make them fit for purpose.
I don't recommend using plain grease, especially lithium based grease as an anti-seize. White lithium grease dries out and turns to a sticky white soapy substance which is perfect for worsening the problem it was supposed to solve.
Grease can wash out relatively easily, especially when faced with the usual regime of aggressive jet washing that many bike are subjected to.
When the carrier medium in most anti seize products washes out you are still at least left with the chemical ingredients there to prevent seizing.
Interestingly, Finish line Ti-Prep is copper based.