You are saying the decision relates solely to a philosophical question. But it can't possibly be answered without considering what it means in practice.
Sometime it is about the philosophical question. For example, the abolition of slavery or and the abolition of child labour had economic implications. But it was still right to abolish them. (And before anyone dives in, no, I am not comparing No voters with anti-abolitionists, just demonstrating from history that it is not always about the money.)
For Yes voters, the principle that a country should be able to govern itself is they key issue in this debate.
All this economic scaremongering is missing a key point in any case. An independent Scotland would be able to grow its economy to be stronger than it is just now, by providing the targeted support that our different sectors require. That could and most probably would include different tax regimes, different business rates schemes, incentives for inward location, support for training... And we would also have the ability to look at developing different models for issues such as transportation and more local sourcing of food which would not only help with pricing but also cut food miles and be more environmentally sustainable in the longer term.
If you listen carefully to what the financial institutions are saying, they are waiting to see what conditions would be like in an independent Scotland. An independent Scotland would have the ability to make Scotland an attractive place for these institutions to do business.