"...those Lee scoopers/dippers/spoonies or whatever you call them..." They're not accurate enough. They'll can vary the charge by as much as a full grain plus or minus. Lots of match shooters load on the range with portable loading equipment. Usually bolted to a solid portable bench. Benchrest shooters do it all the time.
"...volume measuring was plenty good-enough..." Depends on the type of match, but precise it isn't.