Everyone except small market teams and their fans, as they can't just buy their way out of mistakes.
They also will get outbid by big markets who can weaponize buyouts by offering lower salary at much longer term, knowing it's going to be bought out halfway through ... If I get an offer of 4x5 from a small team or an 8x4 from a big team with an understanding that it'll never make it past year 4, guess which one I'm taking?
That also has the side effect of big teams essentially being able to buy a lower cap hit for equivalent value players.
Of course young star players on small markets will quickly see the value of bigger money, and the ability to go get another big contract after a buyout, so they and their agents will quickly force their way out of the small markets ASAP.
So back to the era of haves and have nots.