You have to hold the fund on the ex-dividend date...
Pays out once in Dec. If you buy in Feb and sell in Oct, you're not getting your dividend although you earned most of it... If you had VTI, you'd get 3 of them.
I'd also thought your idea sounded like it made sense, sort of like how a trader can attempt dividend stripping, but looks like the user baking cleared that up.
They raise a good point, which I've never considered before. This could be considered a form of dividend arbitrage based on the difference in scheduling between the component dividends vs the fund dividends, based on the knowledge that a non-zero amount of fund holders will exit the fund before the once a year dividend date, but not before the fund earned dividends based on the fund components.