Do you think joining something like the EU is as simple as a single sentence ffs... That is some lazy fuckin mental gymnastics if I ever saw it. The Luxembourg Report prepared in accordance with Article 126(3) of the Treaty". European Commission. 12 May 2010., actually gives a little more detail rather than that single sentence you gave.

Not to mention, what you said does not even mention any of the criteria required. As some countries can join without adopting the Euro (UK for example).

The requirements to join is a deficit of less than 3%, Scotland has it at 8.6%. But sure, that single line you posted has me and every other source on economic rules of joining the EU just so proven wrong.

Learn some better mental gymnastic techniques.