'Functional' football can mean lots of things to lots of people, which is why it's easy to understand why you might be feeling confused. The most generally accepted idea of functional football is 'unspectacular but efficient football'. As such, you could well be right in your analysis of it there, but not in every case.I suppose I don't really agree on the interpretation of this style of football, maybe that's why I'm confused by the term "functional football". For me it suggestions playing the easy passes without getting out of position too much.
Uruguay and particularly Germany excelled at the last World cup as they always had two or three off the ball runners getting in between the channels - mainly Suarez for Uruguay and Ozil for Germany. Strikes me as being balanced but very fluid and creative.
All the things we're not..
Any team can adapt and employ a functional style to fit them without straying too much from the core principles of it. For example, Zambia in the ACON were undoubtedly a functional side, yet their passes were almost never easy and simple: rather, they were focused on playing on the counter. As the OP says, their idea was to get the ball from back to front as quickly as possible in order to release their front four. As such, their passes were often long and risky.