Plenty of independence. Panama, for example, does not have an independent currency, has significant 'independence', and has one of the fastest-growing economies in Latin America (and beyond).
I didn't downvote you, but I'll voice a similar concern. In my case, influenced particularly by observation and commentary from Paul Krugman. Who's been pointing out the role of adoption of the Euro in what's been playing out in Europe for some years, now.
Currency seems to be a large, unanswered question -- or rather, concern -- in the Scottish initiative.
Smaller countries means more borders where movement of goods or people can be tracked (papers please).
Smaller countries have less resources to defend themselves from multinational lawsuits enabled by free-trade agreements.