What did a glorious temple like the Pantheon in Rome help to serve the Roman Empire in some greater way?

Answer 1

I think it's a little different from mere showiness.

Rome had an official religion, and the Pantheon was the national temple. It was probably more analogous to Westminster Cathedral for England while the monarchs still held substantial power.

Westminster is where the kings and queens showed that they had God's backing, and the Pantheon played a similar role in the Roman Republic.

America specifically does not have an architectural symbol of the supernatural world's role in government, aside from inscriptions and other superficial matters. The pillars (almost literally) of the American system of government are secular.

I am tempted to argue that the World Trade Center was the symbol of our national faith, but wealth is not a supernatural entity, no matter how far out of reach it seems at times.

Answer 2

same as How does the Empire State Building serve the U.S

answer: "we are great, look at our building."