This is helpful thanks! Duo allows Hochzeit to be translated as both, (and rightly so, because 'marriage' is used both ways: normally we think of 'marriage' as the married life, but technically it can also mean the act of marrying two people - a 'marry-age'). I was going to ask if this sentence could be taken to mean "Marriage is beautiful" referring more generally to the institution than a specific marriage, but I think this answers my question. The Hochzeit in German is referring specifically to the celebration and never the 'institution of marriage'. Would that be accurate?
That's right. The 'institution of marriage' is 'die Ehe'. The official part of the 'Hochzeit' is 'die Eheschließung (or 'die Heirat) beim Standesamt' (in the registry office) the second part is 'die Hochzeitsfeier' (wedding celebration). Often there is a 'kirchliche Trauung' in the church, mostly a few days later, and a second 'Feier' with having large company.