If you're building large quantities of forms using the same data fields over and over it might save time. It did on one app where I had 5 multi-page forms each one looking at the same 3 main tables in different parent/child relationships.
However, in most apps if you're repeating fields you generally drop them into a class/container anyway for update reasons. I don't use captions any longer except when I'm repeatedly writing tables out to Text files to show their structures or when they're going to be used in a report writer like FoxFire! which uses the captions in the user interface.
>But, the DBC captions are automatically used when you drag&drop something from the forms DE to a form(UI), I think thats their only good. And for distorting Browses apparently :-)