Welcome. Is it worth it?
Well, here's a case where the additional cost and benefit are inversely proportional. Having status and a 200CHF ticket isn't going to make the airline want to spend a thousand in you on that flight. But it's nice, especially if you fly a lot. And if you fly a lot, maintaining status should be easy.
otherwise, in practical terms, you're looking at 550 CHF R/T in business positioning to Barcelona, and then a weekend ticket to KRK (BCN-CDG-AMS-KRK) for 780 CHF. Throw in three nights in hotels, and you're looking at 1600 CHF for 150 XP, or half platinuplatinumi.
in theory, if you do that for five years, you'll get PFL.
But I would recommend thinking about PFL as something you probably won't get.
After all, what FF programs these days go ten years without major changes to qualifying? Or creating a new level that makes the old one less useful? If you've got to spend significantly more to qualify, then you're spending money on the hope that FB doesn't change, and history is against you.