Why know OOP and templates in the frontend?

Question

Frontend

Good evening.
I understand everything, but for half a year of projects, I saw that the tasks to transport with api are just data, and what kind of behavior should I use?)

Answer 1

No need, kill it.
The best template is copy-paste.

Answer 2

Layout !== frontend
When you write frontend you will understand

Answer 3

Then why and in any other areas of development. To write more complex code while keeping it fairly easy to maintain.
Specifically, for those tasks that you saw, this may not be necessary. Depends on what you are doing. You can live without OOP and patterns if you do fairly simple things.