The method getPrice is not really correctly named if it did the things you describe. Naming things carefully will give you far more productivity than "unrolled loops, toggleable debug logging and comments on why stuff is done the way it is".

Functions aren't always refactored to their perfect names, for multiple reasons.

getPrice might start up as something that just gets the price, after 5-10 years it might be a complex process accessing some ERP systems.

> Stuff breaks, code is read and debugged more often than it's written. Optimising stuff to be easy and fast to write is the wrong way to make maintainable code.

This is exactly why people like collection functions. For loops can do anything, you have to spend more time reading and understanding the loop to build your mental model of what is happening. Mapping does one thing, transforms a collection into another collection. Same with filter, etc. If you are optimizing for readability, collection functions give way more information to the reader. Your approach is to optimize for debugging, which I'm not saying is wrong, but it's not optimizing for readability.

What map returns greatly depends on lambda inside. So yoir collection of beans is changing into collection of good knows what and you have to keep while chaining in mind - because it is nowhere visible.

Whatever exists inside the map lambda would have to exist inside the for loop as well. So if you're dealing with a confusing transformation, a loop doesnt offer you any extra tools for making that transformation more apparent to the reader. Loops have plenty of advantages (computer execution is more obvious, stack traces can be cleaner, easier concept for beginners to grasp), but I have never seen a loop be more readable than a well written functional composition.

Yes and it tends to be more apparent what is its type. It also tends to have a name that helps understanding a lot . It is not even primary loop vs stream difference. This particular frustration is the fluent api vs procedural difference.

It is chaining that obfuscates in this case. Through, I really don't find functional style more readable in general.