That assumes the niche is centered geographically in the west. Online video is an example where lots of people have interest. I see some limitations with tools

That assumes the niche is centered geographically in the west. Online video is an example where lots of people have interest. I see some limitations with tools like PayPal unable to operate in certain countries. Also, translation is lots of work, best left for later. But the biggest reason I think it makes sense to keep the rest of world in mind: there are hundreds of millions of potential users. I don't say billions because the percentage of the world connected to the internet isn't big enough.