"can have more than one app in a Django project?"
Can yes
"If so, what’s the point, when will I need to have more than one app?"
Organizing.
Take the test of creating two more app in your project, register us Settings, create templates, register templates on admin py. and enter the administrative area.
The real need to have more than one app can be personal (or even have some other advantage that I have never tested, such as copying(crtl+c) the app and inserting it into another project, packaging it and installing via Pip as indicated in the link sent by bfvaretto...)
I believe that everyone who starts with Django asks himself that same question - (I myself thought about it a long time ago) - and I see no problem in making it, however it is like cooking beans, we need to risk a little more, test a little more, miss a few times without fear of creating a black hole that swallows the Earth or invoke Cthulu
https://docs.djangoproject.com/pt-br/3.1/intro/reusable-apps/
– bfavaretto