Why Experience Manager need to be installed for the DXA?

Question

DXA requires installation of the following SDL Web Software components :

1. Content Manager
2. Experience Manager
3. Content Data Store
4. Content Service
5. Deployer Service
6. Context Service
7. Discovery Service

But why does DXA require XPM to be installed?

Answer 1

Experience Manager doesn’t have to be installed, but DXA has built-in support for XPM. This obviously won’t work if you don’t install XPM.

But, again, it is perfectly possible to use DXA without XPM.