Because its A73 core are faster and clocked higher than the Pi 4's A72 cores and its GPU is more powerful.
The real question is why you'd want this over an ODROID-N2. That, I don't (yet) know.
I see most of these kind of articles from Tom's Hardware in my news feed, and a lot of it makes me upset because I know for a fact the article writer hasn't tested the hardware, just quoting specs.
On paper and real-world are two very different things.
Please see my previous quote but I agree, the Odroid-N2 comes from a very established brand (HardKernel) with excellent community support, and at the price with specs, it is no contest to go Odroid-N2. If you are new or even intermediate to SBC's, most people will want to go with a product with a strong community so you don't end up with paperweights waiting two years down the road for a stable image.
I bought a Banana Pi M2-Zero and it was about a year and a half before I got a working image that didn't overheat, and there's still no hardware GPU acceleration.