In businesses of the past, backend was highly prioritized. You made a backend, and then you slapped something together for users to interact with it. Normally, you wouldn't give the interface a second thought. In recent years, however, user interfaces (UI) and user experience (UX) have both become dramatically more important in today's increasingly complex world of web development.
Some of the best examples are those of top tier companies. Take Netflix, for example, a company worth billions of dollars. They have a vast library of content, and an extraordinarily large user base.
They wouldn't have as many users if their UI and UX weren't up to par, though. Just think about it. If you wanted to watch something like Stranger Things, and it took you more than 30 or 60 seconds just to find the title and start watching it, would you really want to watch it anymore? A person's mind is very fickle and it takes less than a second for a person to change his or her decision. That's why Netflix utilizes UX to streamline the interactions required to start watching a show - just type a term, click, and you're ready to start or continue where you left off!
Compare this approach to something like on-demand television - you grab the remote, you have to navigate to the network, then the show you want to watch, then the specific episode - certainly a lot more interaction required there than with Netflix.
In 2020, UI and UX couldn't be more important. This blog looks really nice so maybe that's why you're interested to read some of the articles? If it looked anything like this:
Would you really still want to be at this site? Probably not. A website that looks and feels nice to a user will instantly be more successful than a website with a sub-par UI and UX, even if the website with a worse UI does have a better backend. Users aren't gonna see what's in the back - only what's in the front.