I would agree with you, but in my experience the “next next next done” approach is always a failure…
I’m quite sure that such an approach is usefull for a skilled user too (easy tool) that knows what it’s going on behind the scene…
but there are “common users too”… how many web servers with wrong permissions did you see during your life?
the point is that as long as your (generally speaking) server is inside your lan and is not reachable from wan and doesn’t connect to wan itself, you’re free to do everything as you prefern, even without knowing anything about web, mail, spam and so on…
in the moment you connect your server to WAN, your server could be a problem of mine, 'cause an hacked server (and with hacked I refer to web applications, not the server itself, that is very, very hard to hack) becomes a enemy for me, you, everybody… and, if you work daily with spam or phishing you’d know what I mean…
NS is easy to setup… install it as a bare system, configure it…
then add what you need (and to choose what you need you have to know, what you need), install the packages (and you have a user friendly UI to do so, so a very easy operation indeed) and configure them… you’re done…
so, in the end, since is ALREADY so easy, why do you (generally speaking) need anything that make it easier?
finally, knowing what you’re doing is necessary NOT when you setup a server, but when you have to debug a problem… and if you take a look on windoze side, the “next next next done” approach has made so many damages that no one here can imagine.