Data Transfers · Data Transfers basics
Should I use Data Transfers to copy everything to a new external drive?
Short answer: Not for your Storage Studio drive. Use Transfer Drive (More → Drive), which copies, checks, and re-points every relocated app and folder to the new drive. A plain copy wouldn't update those shortcuts.
Not for your Storage Studio drive itself. Use Transfer Drive (in the popover's More → Drive section) instead: it copies everything to the new drive, checks the copy, and then re-points every app and folder you've relocated so they keep opening from the new drive. A plain copy with Data Transfers wouldn't update those shortcuts, and your relocated items would still point at the old drive.
Backup Drive in the same place makes a verified spare copy while keeping your current drive active.
Data Transfers is the right tool for ordinary folders that aren't relocated by Storage Studio.
Related: External drives