[EDIT]: He's a Phd for chrissakes!
And yes, if the whole point is to utilize AWS resources, then of course a architecture like that is fine, as it's a learning exercise (to learn how to utilize resources). My comment includes that as well.
As far as I can tell, the author is studying at a university, that makes them a student in my mind. Maybe they do other things than just studying, I didn't look into it very far, hence the "maybes" and other caveats in my initial comment.
AWS is more reliable, and from this architecture, probably doesn't have to do anything. If the VPS dies, then the site is down until can build new VM. Or have to run two of them at twice the cost. More since he has to setup database or shared storage.
That might be overkill for this site, but for some upfront work, he gets something that needs less maintenance. If going to learn, then should do it the right way. He may be scaling for the future, but it is tradeoff to design now instead of later.