For me it depends on: what is the purpose of governance? Is it to make things clearer and smoother? If cross-circle role references reduce more tensions then they cause, I would tend to favour it.
Although I do like your point Xavier, because I think allowing the team structure that needs to be to evolve is a great feature of Holacracy.
This makes me think of Large Scale Scrum and the concept of Communities of Practice.
So, we have a Finance circle. There's a whole load of work that happens around finance, and so there are a whole load of roles.
Is it "better" for these roles to be distributed around more so that Circles become more like totally self-sufficient wholes? Which then opens up a space for the various finance roles to meet as a more informal community of practice?