The only downside I see to it in racing is that if you want to do a head sail change you'll need a second sheet. With bowlines you can untie the lazy sheet, tie it to the new sail, tack, and then do that again, then lower the old sail.
If you're on a long leg you might not want to tack, so you can't do that anyhow and need a second sheet.
But a second sheet is just as good. If you do this you might want headsail lead cars that have a block wide enough for two sheets, but its not really a big deal.
who races with only one set of sheets?