Your answer was a tad bit snippy. I know had a choice; didn't need you to tell me that.
Erm, re-read your own question: you are asking everybody else why you'd want such an address. To me that comes across that you didn't know you have a choice, especially since you list a lot of services you have. That comes across as desperately trying to fit in and register with any service there is.
The point is that you are asking others to do something only you can: decide if it is useful to you or not. If you check out apple.com/icloud you get all the information about what it is and why someone would want iCloud. Some people use it for everything it offers, some only for email, calendar and addressbook (like me). Some don't use it because they have Gmail or some Exchange account. Again, you are the only one who can decide if it offers you something or nothing. Checking out apple.com is the best place for making that decision.
Apple introduces a new service in which all of my devices can be kept in sync. They also ask me, at the same time I set the service up, if I want their email address. It shouldn't be a stretch for anyone to wonder if there is a necessary connection between the two.
From what I recall you can get more information about that in that particular screen. You can skip that part but this isn't very obvious. To users it seems that you have to use iCloud for it to work while in fact you don't. Apple should imo make that more clear in that screen. It is the same thing as with the OS X setup and the AppleID and registration (you can skip both but it is not clear that you can to the user). This is just one of the ways of getting people to use iCloud.
The next time you decide to help someone out, try doing it with a less condescending attitude.
Next time try not to take everything as something offending. In this case there really was no attitude whatsoever. The way you are reacting now makes others very reluctant to helping you out.