I think you are absolutely right. I kept bees in the UK for many years. Crystallisation from OSR (Oil Seed Rape aka Canola in the US) was a problem, but it would be a problem for both traditional and Flow hives. If you can spin honey out of traditional frames (you can’t if they are crystallized), then you can use Flow frames. No problem.
When you drive along the motorway and see the OSR flowering in vast yellow swaths, just make sure your Flow super is off, or harvest within 2 weeks even if not capped. Same as for traditional hives. I don’t like OSR honey anyway (anyone for something that smells of old gym shoes and overcooked school cafeteria cabbage? ), so I would never have a super on when I could see it flowering within a couple of miles of our hives.