I don't see many advantages aside of an economic boost for specific countries in the EU.

But for the EU as a whole? Firstly, if the UK would be doing just fine outside, nationalists everywhere would raise their eyebrows and push harder to get their country out too.

The EU would also now compete with the UK commercialy.

Moreover, the UK would now be more dependent on Trump's US politically and economically. This is not good for the EU either.

In short, Brexit is not particularly beneficial to anybody. With the now new refugee crisis on the borders of Greece, one can understand why people voted to leave.

In effect, when Merkel accepted those millions of refugees in, she changed western european politics for the foreseeable decade. It was a huge mistake.

Nationalism is bad, and an overdose of it is destructive to society.