Welcome to the game!

Yeah I think it's mainly because the journey to level 80 would be very slow as much of it was original balance to progress you to 50. But kudos for wanting to try out your abilities as you learn them and getting the practice with using them. I generally think it's a good way to learn. I guess bright side is you won't ever have to play catch up, like some of us old timers have done. Like being level 47 and finding the next quest is a level 49 requirement and you've got to grind 2 levels to continue.

There are some side 'optional' dungeons, but I'm not sure if they're accessible unless you're at certain points in progressing them MSQ.