Currency union would protect historical ties
IT is bad enough that Scotland wants a divorce, but it is worse that the UK wants a messy one, as it does not want any currency union with Scotland.
Given that Scotland and England have a shared history that goes back 300 years, and 51% of Scots now want independence, any long-term solution would have to include some sort of economic mechanism to ensure that these historical ties are preserved.
With the currency union, an independent Scotland would remain, albeit nominally, a part of the UK. Without it, it will be like any other foreign country. The currency union could work in the interest of both countries.