It's not being disagreeable itself that's bringing those benefits, it's the unpopular but necessary decisions that are getting made by being willing to stick your neck out and piss people off.
In many situations the popular decision is not always the right one. People frequently approve of decisions that bring them personal benefits or ego gratification at the expense of the group, or that seem beneficial now but have hidden downsides that they don't know about, or that bring short-term gain but long-term pain. Saying no to these decisions isn't going to be popular, but it's necessary for the long-term health of the team.
Rational employees can see this, and can see the consequences of always giving in to what the more vocal team members want, and so they quietly hold leaders who make the right choice rather than the easy choice in higher esteem. It builds trust with the team to show that you understand the difference and won't let a need for approval cloud your judgment.
The idea that being disagreeable itself is an advantage in business is sometimes known as the Steve Jobs Fallacy, i.e. "Steve Jobs was an asshole and he was successful, therefore I'm going to be an asshole too and I'll be successful." This fallacy ignores that Steve Jobs was an asshole in pursuit of something greater, that a lot of his tirades and emotional manipulation were tactics to draw peoples' best work out of them and build really great products that consumers love. The key part there is "build really great products that consumers love" - if you can do that without being an asshole, you'll be even more successful than Steve Jobs, but that's the high-order bit. (Arguably, some of Steve Jobs's verbal abuse was gratuitous, and the same product goals could've been achieved with less emotional pain.)