Basically the E111 allows you to get health treatment like any other member of that country.
It has absolutly nothing to do with payment.
It ensures that you GET treatment, but you will have to pay for it.
I'd say it was a stupid thing to do, personally.
Even the treatment for a hypo could run into £1,000... ambulance, glucose, monitoring etc....
You were lucky nothing happened.
I developed pancreatitus in Switzerland... 3 days intensive care, 5 days normal. 3 scans.
Over £17,500.
Insurance only cost me £200 for a year, including extreme sports coverage.
It's always good to get it.