I wasn't sure if this was really the right place to bang on about the features in "off topic" software, so I didn't include this bit:
I guess the answer to the original question comes down to what the user wants to do.
If they just want to use DOpus to copy or move files around the place, then it makes much sense to shut down Outlook and any other programs that might have PST files in its clutches, and then to do their dirty work.
If the aim is to set up a system for doing fancier stuff, then alternative tools might be a better option. For example, if the idea is to create a backup regime – surely the sort of person who buys DOpus has this embedded in their daily routine – then it is probably better to use a specialist tool unless they have a truly simple setup.
I make no special claims for SyncBack. It is just the software that I have used for many years. But when seeking backup software it clearly makes sense to investigate how it handles PST files.