Generally a dash is used here just as so called copula is used in English. So your guess is right, dash here is a some kind of punctuational copula, therefore can be translated as "is".
Though — это
is indeed another form of such copula, there is a subtle difference between usage of these two forms. Roughly speaking, pure punctuational form is more universal, you can use it in a wider set of cases.
You can say, for example:
Вы — подлец!
But this phrase will sound definitely unnatural to native speaker:
Вы — это подлец.
So, with personal pronouns usage of это
is untypical.
As for me, it is very difficult to describe exact rules for choosing one these forms, but here is a rule of thumb that can give you a hint. If you can imagine the phrase used in some kind of dictionary as an article, for example:
- Париж — столица Франции.
- Слон — млекопитающее.
- Солнце — звезда.
then you can use — это
form.
Also, when you want to emphasise the second part of phrase, you can use это
. So, when you can imagine this very phrase used with some adjective, it looks like you cane use - это
form:
Пётр — [это] [ужасный] негодяй.