Hi there If I understand your question correctly its not about what is in demand it is about which location can help you best serve your users based on traffic and desired audience
True its hard to help with such little information but location depends on any number of factors as i pointed out and i would hate to give the wrong advice
if i had to give blanket advice for this i guess it would be
Dallas Chicago and Seattle locations can serve North America well a Singapore location can serve East Asia (India, Australia, Malaysia..ect), and Germany for EU hope that helps there is no best location of anything unfortunately but there are good reliable or great services still depends on your needs
Almost time I chose a server, the country that I would like to pick is USA.
Why?
Because I want to target audience in that country, choosing a location there will help my website loads faster and it is also better for SEO when choosing a country that you are wanting to get SEO benefit ffrom that country.
Hi I have said before that this question does not make sense location only matters for audience and geographical strategy and nothing else as long as you can effectively serve customers that is what matters there is no magic location