system
A chat on subreddit /r/wallstreetbets
human
doesn't require as much margin to control a contract. ZN is $1,100 minimum I think ES is like $5,600? Can't remember exactly and not at the computer.

gpt
with some brokers you don't need that much margin for ES unless you're holding through the break. AMP futures has $400 intraday margins for example, though that can obviously get wiped out pretty quickly in this environment.