A 4-3 trump fit is known as a "Moyesian" fit after an expert who liked to play such hands, even with fewer trumps than the standard eight card fits.
Their main downside is that with six cards in the opponents' hands, one opponent would occasionally have a longer (five or six card) trump suit than the declarer. This would lead to control problems, and potentially to large sets.
In duplicate bridge, particularly matchpoints, the frequency of the wins is more important than the size of the wins. In my club, at least, players that bid good Moyesian fits (those with good high card control) tend to do well in the scoring. The boards on which they lose to long opposing suits don't hurt them much because the size of the losses don't matter as much as their rarity.
Would playing Moyesian fits generally be a better idea in duplicate, given the differences in scoring between rubber and duplicate bridge?