Why would you use a library or framework when you can code everything from scratch? It probably depends on how good the VSCode extension is vs how bad the IDE is.

For the languages I have tried (mostly GoLang plus a bit of Terraform/Terragrunt), VSCode plugins can do code highlighting, can highlight syntax and lint errors, can navigate to a methods implementation, the auto-complete seems to pick random words from the code base, and can find the callers for a method. It is good enough for every day use.

IDEs I have used (Eclipse for Java, PyCharm, InteliJ for Kotlin) offer more. They all have starter templates for common file types. The auto-complete is much more syntax aware and can sometimes guess what variables I intend to pass in as arguments. There is refactoring which can correctly find other usages of a variable and can make trivial code rewrites. There are generators for boilerplate methods. They all have a built in graphical debugger and a test runner.