I have found many benefits of having DXA like lesser dependency on core SDL Tridion knowledge, faster Publishing etc. But technically, I want to know:

1. Without having DXA I can achieve the same architecture where my Component Template serves the content in JSON, then why do I need DXA?
2. What exactly will I get in DXA, will the Content Delivery APIs be replaced with some more optimized API, as today too with SDL 2013 SP1, we are using Spring MVC on the front end?
3. Won’t DXA bring more performance issues as every small content will then be coming from Broker DB?

Thanks in advance