Yes, that was the reason, someone else already made a higher bid.

Through kingofeos.com it works only through Scatter.
However, you can directly communicate with the EOS contract from the command line through cleos. But then you can't set a flag image and it's not really user friendly as it's mostly a developer tool.
Not sure if people are doing that or if they are just fast clickers.

Too bad you couldn't get in, maybe next time ;)