"I sleep a lot because I am young."
Translation:Eu dorm mult deoarece sunt tânăr.
Basically none. However, Romanians are obsessed with cacophonies with /k/, so they would use "deoarece" to avoid it:
EN: I am getting tired because I am carrying heavy luggages.
RO: Obosesc pentru că car bagaje grele. - cacophony
RO: Obosesc fiindcă car bagaje grele. - cacophony
RO: Obosesc deoarece car bagaje grele.
Disclaimer: my own edgy view
You shouldn't care about this, as a cacophony is basically just an alliteration that some random people arbitrarily consider unpleasant.
i believe that's only used for negative cause-and-effect situations. e.g. "i'm late because of (the) traffic (jam)", there you could use it. or "i'm fat because i eat too much" - basically a fault/flaw. but the fact that a person is young is not considered "bad" here.