I just asked the question and I just looked into this more as I've built my front-end in Django already. Might have a play this afternoon a little bit more and see if I can split it.
but I did come across this handy article which clears up as to the reasons why. I hope it helps others like me who get simply confused at points haha
https://michaelwashburnjr.com/4-reasons-web-app-separated-frontend-backend/