It's all about scaling of complexity and number of engineers working on the project. No doubt hand rolled js is better when you only have to do the one thing you mentioned and you're the only person who has to read or write the code.
What happens when it's one of hundreds of checkboxes on the site? When they all do slightly different things depending on user sku, product page, file type, file permissions, god knows what else. And when one experiment flag is on or how about this other one? Then i18n? Then what about the fact that after you write this line countless other engineers will see and modify it in the future, it's not just you writing and maintaining it? These are the problems that my company (and, I assume, Publicis Sapient with 20,000 employees according to Google) have to consider when choosing whether to hand roll JS or use a framework.
What happens when it's one of hundreds of checkboxes on the site? When they all do slightly different things depending on user sku, product page, file type, file permissions, god knows what else. And when one experiment flag is on or how about this other one? Then i18n? Then what about the fact that after you write this line countless other engineers will see and modify it in the future, it's not just you writing and maintaining it? These are the problems that my company (and, I assume, Publicis Sapient with 20,000 employees according to Google) have to consider when choosing whether to hand roll JS or use a framework.