A domain name is like a signboard on the internet; you purchase it, and people find your shop through it, where you can offer a variety of things to those who come here. It doesn't necessarily have to be a shop; it can also be a display board showcasing what you want to show everyone.
Clearly, in this process, the domain name serves merely as a signboard. Aside from telling everyone where to find you, it doesn't serve any other purpose. Therefore, in today's internet age, with the emergence of various social media, people can have their accounts on different online platforms, posting everything from text and images to videos, or even sharing any files through a cloud storage service. The account itself has become people's new "domain name," and it may even be free, hosted on a larger social network, making it more powerful in some respects, until... you become a bit "rebellious," "rebellious" enough that the platform no longer provides you with a "domain name."
However, a real domain name is different. Even if you don't need to be "rebellious" to the point of not having an account on social media, you can still gain some advantages that only a domain name can offer. Platforms may disappear, user rules may change, and published content may be taken down... but currently, in the known history of humanity and the visible future, people's internet experience still cannot do without domain names. This means that having a domain name ensures you a permanent place on the internet (as long as people still remember you).
I know that maintaining a website behind a domain name, or using various page hosting services, as well as the annual domain renewal fees... these are not small expenses. Although many people today own a domain name just to host their blog, it can still provide you with a cyber business card. This card may not be large, but through free web hosting services, it can at least showcase a lot of text, images, or videos, and even leave your new platform address under the website of this domain, telling people where to find you on the new platform.
As for the expenses, I want to say that for an adult who can "wander" on the internet and has a job, an annual renewal fee of over a hundred (RMB) for a domain name is really not expensive (unless your domain name is very "eye-catching" and costly). If you are willing, you can even "host" under a friend's domain name using a secondary (or tertiary) domain (laughs). Or if you are not yet of working age and no one is willing to help you pay for that expense, then I think it might be too early for you to own a domain name.
For users within the mainland internet or other networks with censorship mechanisms, your domain name may not be able to provide services due to content or various reasons, but it is best to comply with local legal requirements beforehand. My advice is to be a friendly person :)
Postscript: The idea for this article comes from an ASMR creator I follow, who uses a domain name as her "business card."