Why should we use Docker and Kubernetes instead using Heroku, for Django?

Currently I'm developing my website using Django and Heroku.
But I want to upgrade by using React for my front end.
I know react would give me great benefits for front end, I understand the benefits.

I've seen recommendation that using Docker and Kubernetes with Django will be good than using Heroku. I still don't understand why.

I'm new to these things.
Can anyone here please refer to me such links or explanations about "Why should we use Docker and Kubernetes with Django?"
I believe that using Heroku too much will cost high with scale that goes up really fast.

I need some kind of enlightment of Docker and Kubernetes uses with Django.

Where are the points that those things connected.

For example React, React is for front end part. so Django can be full on the back end. Data Integration using Restful API.
React replaced Django templates using components.

How about Docker and Kubernetes with Django, compared to Heroku with Django?

Thanks

Comments

[Naman Gupta]

I am not a django developer bt write backend in NodeJS. If I understood in the right way then by heroku, you mean some kind of managed solution by Heroku. (Correct me if wrong). Docker and kubernetes comes into play when you want to manage infrastructure (Cloud) by yourself. There is no WRONG way. Its just depends on use case. If you are building a side project then you can go for any. These things come into play when you talk about medium to large scale. Developers like me loves managed solution (Heroku) as it allows me to invest more time in code. Currently I prefer writing backend in serverless instead of deploying whole nodejs app. You can do the same by writing cloud function in python and writing your frontend app in React. Again I would repeat it's just personal preference and use case.