The same could be said of many things that, nonetheless, are still used by many, and will continue to be used by many for decades to come. A thing does not need to be best to justify someone wanting to make it a bit better.

I use plain old zip files almost every day.

“Best” is measured along a lot more axis than just performance. And you don’t always get to choose what format you use. It may be dictated to you by some 3rd party you can’t influence.