//If someone says that a Brexit benefit is being free of the EU, they need to expand on that...//
Not necessarily. I disagree with the basic tenet of the EU. It aims to promote itself as a single entity. With its borderless Schengen area, single currency and common policies (its foreign policy in particular) with which its members are expected to comply, there is no doubt about that. There is also no doubt that it has ambitions to enhance and reinforce that philosophy and its progress will not be thwarted by any pesky and truculent individual member nation. For that alone (though there is much more besides) I do not want the UK to be part of it. So for me, leaving is not the process, it is both the aim and the benefit.
That is why the benefits and disadvantages of leaving are of little interest to me. There are no benefits so great and no disadvantages so dire that I would prefer the UK to remain in such an organisation. I know that is hard for Europhiles to understand this but it is my point of view. I had one vote, the same as everybody else and I cast it the way I did based on that point of view. My belief is that you don't sell your soul for thirty pieces of silver (or, in this case, the possible odd percentage point increase in your country's GDP). And membership of the EU is, IMHO, very adjacent to selling the nation's soul.