It has always seemed to me that this division between root and standard user on a single-user machine is kind of silly. Yes, you can trash your machine as root user, but you can trash it because of this forced division too, as the previous commenter shows.
On multi-user machines, having separate user accounts that are not allowed to intrude into each other's account or to meddle with the machine's core programs makes very good sense, but forcing the owner of a single-user machine permanently into this way of working is just plain nonsense. The Raspberry Pi is an experimenter's machine. Keeping the real power out of their hands is a big mistake. Even in the unlikely event of trashing the OS, big deal. Just rewrite the flash card. That's why the Pi was designed with the OS on an ordinary flash card.
I use various versions of Puppy Linux on all my computers at home. Puppy Linux logs you in as root as standard practise. Certain processes get run with restricted rights but the human user is root user. When I was learning about Linux many years back with Puppy I did trash my system a few times, but it was never a big deal when re-installing is so easy. (Puppy is about 100MB and can be run off CD without actually installing if desired.) And I'll bet I learned lots more about Linux in the process than people living in the cotton-wool "protected" world of sudo.
Consider people who don't let their kids play on the swings or let them climb trees, or swim without floaties. The over-protected world is an impoverished one, and paradoxically dangerous one. If you break a limb when you're young, it mends easily, whereas breaking that same limb as an adult can be catastrophic and it might never mend properly. Similarly, breaking the Pi's OS is not a big problem and is easily fixed, but if you graduate to a job on a big computer where your inability to understand the consequences causes millions of dollars worth of damage... well... you get my point. Best to really understand on the little, easily fixed one.
I think the disallowing of root access has become part of computer myth, like the mistaken, but incredibly widely held belief, that the GOTO command is bad. It became accepted into computer folklore without any real basis in experimental fact.