Of course, you are correct, Joe.
But this is the Blackpowder forum, and those new fangled plasticky thingies haven't been invented yet!
Smokeless powder? What the hell is that?
"You certainly don't want to use a dispenser with a steel or iron gate in it, but you'd be nuts to use one of those for smokeless as well."
On that I'm going to have to disagree.
Many current measures designed for use with smokeless powder, including the RCBS Uniflow, Midway's units, etc., use iron and/or steel rotors, slides, etc. without issue.
I've used my Uniflow on and off for over 25 years without an issue.
I do use a Lee Pro Disk for my general handgun loading, though.