Correct me if I am wrong but was not Salmond not having any credible answer to what an independent Scotland would use for currency the main reason why the independence vote was lost?
You
are wrong about that.
However, I do think the SNP's currency strategy was a mistake. Not because they didn't have credible answers: they did. What they mainly had was a presentation problem. You can read the whole story here if you are feeling particularly masochistic:
Will you vote for independence? Many of us who are not in the SNP felt irritated at being expected to explain a policy we didn't agree with.
The strategy they opted for in general was to not give make too many changes, so that independence wasn't scary. But the trouble with that was that if too little changed, people start to wonder why they should bother. Isn't the point of change to make differences?
The four currency options they gave were perfectly coherent, credible and workable. But their preferred option (using Sterling) was the wrong one. It made it appear that currency was something Westminster - Osborne - would have to grant. This is a tactical error. It also meant that too many economic levers had to stay at Westminster. (So what, you might say, the euro zone has the same problem visa vis national sovereignty. But if you're selling change, it's another own goal to say you don't have this change available). So those were the presentational problems. Which Salmond miraculously overcame when in the 2nd TV debate Darling stupidly lost the whole country on his one advantage by being a twat. So, the issue stopped being a problem in the public perception. Salmond didn't win it. Darling lost it.
However, and more importantly, I had a problem because it was tying the country's economic policy to Westminster in a practical way. I thought the best option was a separate currency, the Scots pound, which should probably initially be pegged to Sterling so that there wouldn't be destabilising trading (in either direction) on the currency in the launch period, possibly 18 months, but the time scale not set (at least not publicly). It would then be unpegged.
That's last time. This time different conditions apply. We await what time scale Brexit will have. We await what the economic conditions will be. We await what the terms and treaties Westminster will have negotiated. We await, what is more, the shape of the EU at the time.
New EU members states are currently expected to join the euro as a condition of entry. However, before joining eurozone they have to meet "convergence criteria". This waiting period has proven to be long and without a foreseeable end in sight in a number of cases. In the meantime, they use their own currency.
All of this is still hypothetical until we see what comes of the process Sturgeon has entered into. The stage Brexit is at when Sturgeon decides whether or not to call indyref2 will make a difference.