Small Beer:

I've just had an inquiry from an editor asking what I meant by the expression "small beer" and asking if it was a common expression and whether others would know what I was referring to. As in the following sentence:

When the questions of war and peace were on the table in ways that involved directly the world's great powers, then the NGOs and global civil society seemed small beer indeed.

Does this use of "small beer" seem too obscure? My understanding is that the expression is British and dates back to at least the 18th century in the meaning of persons or matters of no account of little consequence. At least, that's how I've always used it. Am I right and even if I am, is the phrase nowadays overly obscure?