I think it is a matter of being pragmatic and not reinventing the wheel. If you don't need anything different than the tools you are using provide, I think it is ok to just use the tools. If you want to learn how things are done under the hood and you have the source code you can always have a look. If you want to learn to do it from scratch and you have the time, it is ok to take the time to think how you would implement it and work on your approach. If you need something more than what the tool (library, framework) provides, you can either extend it (if you have the source code) or go for something completely different (Monthy Python pun not intended). Anyway... real developers use Vi.
