It is helpful to the core rich countries and to elite/upwards mobile across countries. But it hollows out the periphery.
A lot of the GFC era EU debt crisis was German banks lending to southern European states to then buy goods/services from.. German industry. So I was not as understanding of the northern countries looking down at the "lazy south". It was far more complicated than this and they were happy to look the other way while it worked for the first decade.
I'm honestly not sure where EU goes from here as the GFC & the response dampers any enthusiasm for a true federal government, unified military, etc. Not that there was much appetite to hand over that much sovereignty to start with. Nor does it help that post-GFC, even the rich parts of EU have further diverged in terms of wealth/income from the US, so they are probably feeling even less "generous".
Draghi wrote a whole report on EU competitiveness recently and in standard Eurocrat form its like a 500 page paper no one will read, let alone action.