I've done both over the years. But I have stopped greasing the tapers and if chainline is important (and esp if I do not want the cranks creeping in further) I clean the tapers with solvent. I have observed that greased tapers lead to the crank moving inboard after enough re-mounts to the point where I have to start using longer spindles or shimming the tapers. I have even split a crank.
Now I have a bike set up where I want the chainrings as far inboard as possible to best line up with track hub cogs. So I am using a Phil Wood BB to dial in the chainline so the ring doesn't quite scrape the chainstay paint. I want everything to stay right there. Really dry fits only on that bike.
Like others above, I have never had issues getting the cranks off. And I have never seen evidence of galling in 50 years. So I see little plus to using grease/oil/anti-seize. Just downside; the slow demise of of the crank's tapers. Not an issue if you never re-install the cranks.
Ben