It is still a business, I believe. The difference between a “work-at-home job” and a “home-based business” can sometimes be blurred, but in my opinion, if you are self-employed, it is your business. My father had a business and worked from home – I don’t think it is the same as a remote job.
You are confusing the issue. No one is talking about WFH as a remote worker.
A job is something you do for reward, wherever you work.
A business is something that makes money for it’s shareholders, wherever the business activities take place.
The classic UKBF definition is that a business that can only pay the sole director a wage, and makes no money otherwise is, little better than a job in financial terms. There are obviously other benefits such as flexibility and being your own boss.
A business that cannot function without the director as the one key employee is not a real business.