I also buy stuff and services frictionlessly being outside of the EZ. Why trade away your country's monetary sovereignity for the convenience of currency exchange? We all know what happened to Greece and to the Italian economy.
https://www.ineteconomics.org/perspectives/blog/how-to-ruin-...
This is painting just one side of the story. Look up the graphs for debt as % of GDP in the same years.
https://tradingeconomics.com/italy/government-debt-to-gdp
https://2.bp.blogspot.com/-rj28mXbk6V8/TsEC58hZftI/AAAAAAAAA...
Sure, we were growing, but more than that we were growing our public debt. I'm no economist, but this doesn't seem the sign of a healthy economy to me.
I do not claim to know the aggregate effects, but I would guess it is not as simple as convenience vs. sovereignity.