Talk me into it, folks. What element of skill makes this worth playing?
Combat at it's most basic. One on one. With a decent set of rules it's not just "5+ to hit plus one to the die for a longer weapon," or whatever. You are balancing the risks and rewards. Is a risky strike with a potentially bout winning outcome if it succeeds worth opening yourself up to a potentially fatal riposte? Can you play to the crowd without getting a dagger to the kidneys? That sort of thing.
There's the potential for multi-figure/ multiplayer games too.
And possibly lions and tigers and geeraffs ... aye an' brown ale and sandwiches too! OK cheap red wine, nuts and sausage inna bun.
Or, at another level you may be running a full stable of gladiators. Think of it as the Ancients equivalent of Fantasy Football
You only need a handful of figures and a small play area.
"Are you not entertained!?"