That's the thing though, people who use gold and use the finish now feature extensively will be hardly affected by it, as they will more than likely use it only on buildings that they aren't intending to use the gold feature on - smaller, lower levelled things that take less time to raise anyway so will hardly notice the effects of this new feature.
Meanwhile this feature is available for those non-gold users to use on their own high-levelled fields and buildings. It does reduce the gap in this sense, because it will affect those with no gold much more than those with who use finish now extensively.
I'm no Travian dev, but I'm sure this was one of the goals of the feature, aside form extra revenue gain from ads. And it's a good one, in my opinion. I'll happily agree to disagree with you, and I'm curious to hear what other people think on the matter too.