In an NA application, I can't imagine it would make any difference on the time slip. Unless you're running nitrous on the ragged edge, what's the justification for it? Rock steady timing is neat, but if your timing jumps around that much you need a new chain.
Chain, gear slop, driveshaft moving around, oil pump affecting the whole mess. Plus cam twist if it's a small block. If you're okay with it moving around a couple degrees, then it doesn't matter.
Crank trigger, what you see with a timing light is like a snapshot. Zero movement.
With the ignition stuff available now, you can set the base timing ahead of where you want it and dial in a retard curve. Some guys I know are using various amounts of retard at different places on the track. No reason it couldn't be done on the street. Even dialing in the timing precisely on each cylinder, if you are collecting data.
