- a common currency, eliminating the need to exchange currency - remember, Europe is a lot of small countries and you can drive six hours and pass eight different countries.
- a common border-control free zone ("Schengen agreement")
- a common, free-of-charge mobile phone roaming area
- common consumer protection laws in all areas of business, particularly data protection (GDPR), product safety (e.g. RoHS) and finance
- infrastructure development across Europe (e.g. constructing trans-European highway and rail network)
- a common economic market with the same standards for everyone
When comparing the EU to the US, I definitely prefer the EU, as dysfunctional as it can be sometimes (especially in foreign policy and military).