Sometimes it’s better to code the whole module first instead of debugging and testing continuously. Debugging is very time consuming especially for heavy applications like SharePoint’s.
If the deadline is approaching, at least you have a module that has already been thought out, you can mitigate problems later. It’s a better solution that trying to implement the module when deadline approaches.
For big application, debugging is very time consuming and disruptive to your flow.
Write code in big chunks, then debug once in one session to save time.