Code is easier to tweak than to write.

To write the code from an empty file requires you to free recall all of the details and idioms… easy to mess up, even if it's an environment you're familiar with.

Code that works and does something slightly different than what you want is much easier to tweak to do something you want.

Today, it's unlikely that the code you come across is almost what you want.

Maybe it's tutorial code, or starter-kit code. It works, but doesn't do much.

The one exception is when you're tweaking a project you already use to add just one more feature–the code already roughly does what you want, modulo the one tweak you're making.

But LLMs make it so it's much easier to create working code on demand that you can then tweak if necessary.