Good question, with the rules the important thing is where you are now living (I assume Switzerland), but mostly if they ask documents at the ticket check they look at the nationality. 

Its getting rather vague with these new online apps. You SHOULD buy Interrail and hence can only use it in Swiss for 2 trips. EUrail now cost the same-in the past it was hugely more expensive-so thats the difference. IF they check it-and this will thus only be important In Swiss, you should be able to show some official document that you live in CH-and there certainly must be such a thing and you should know best how it looks like. If not-then youre illegal.

I predict this will be the next big stumbleblock when all the railways decide again about future of these passes-big very expensive countries like UK or DE will not want that people pay much less as theirown network passes.

Thanks a ton for your valuable time and feedback. Much appreciated.