Is vacuum advance needed with MSD box with a daily driver?

The MSD box is not a requirement of the holley sniper... You'd have a double redundant ignition system with no real benefit, and would have paid $250 for something you don't need.

If its running now, you'd be better off to leave it as is, and then purchase the correct and non redundant distributor to go with the sniper.

If you want to dump the mopar ignition (good call) and also have a distributor you can use with the sniper going forward...you should just get one of these.
ready to run, no box required, sniper compatible, mopar ballast and ecm are not used.

TSP-JM7713R Mopar SB Pro Series Ready to Run Electronic Distributor. Red Cap

View attachment 1715043517

you can adjust the vac advance as desired on this one, or remove it entirely.

I know you don't necessarily need the CDI box with the Holley, but from what I understand you have to buy there box for the coil control which cheaper but don't get the benefit of multi spark at cruise rpm.