You can equally accurately say the South got a boost in representation by the 3/5 rule.
The South claimed slaves were property, and was increasingly moving towards the notion that they weren’t really men at all. (This is, after all, the only way to square the sentiments of the Declaration of Independence with slavery.)
So why should southern property be counted when determining representation while northern property was not?
Our founders punted on the issue at great cost to the ultimate shaping of our Republic.
In their defense, it was probably too great an issue to handle in addition to the grest task of building a nation.
Sounds like a bad agreement. If the Northern states had just stuck to their moral guns and refused to make a deal with the Southern states, why everyone would have been better off in the long run. Right?
As it is, they made a morally odious deal, which they subsequently sought to undermine at every opportunity, culminating in them eventually breaking the deal which they agreed to in the first place, after obtaining every possible advantage from it while it lasted.
It helped to secure their independence, it helped to boost their sales and economy, it provided them with much needed capital, and when they became rich, they didn't need it any more. They could afford their recently found morals. Now that the deal no longer served their interests, they could look down their noses at it, but without it, there is a good chance they would still be part of England.
Bait and switch. That was a very successfully played game.