Internet via iPhone's Personal Hotspot vs Cable Internet?

I currently have a data plan with unlimited 4G data with my phone carrier. I can share its cellular connection with my desktop at home which has been working out great even for streaming videos.

Is there any reason we should still buy Internet service from an Internet service provider like Comcast, when all I have to do is use the Internet connection from my phone carrier? What are the advantages?

If your cell phone hotspot is working for you, then there's no reason for any other internet service. Typicly, tho, cell phone data plans tend to be the most expensive and most limited.