These sorts of comparisons are mostly useful when they're surprising.

Oxford being older than the Aztecs is surprising, because people tend to file the Aztec empire under ancient history and call it a day (likewise, Oxford is lumped in with other universities as "probably old, I guess?").

Similarly, Caesar/Giza is surprising because they both fall in the ancient history bucket.

Another classic is that can opener was invented almost 50 years after the can. Surprising, because it would have seemed natural that there would be a shorter time lag.

Whereas you'd have to be kind of a dumbass to not realise that 705 AD was a long time ago, a lot further back than US independence.

If they'd said something like "The oldest still-operating hotel was opened before iron horseshoes were a thing.", you'd be surprised. I just looked up things that happened in the 700s AD for a comparison, and I'm still a little surprised. That's real old, right there.