The main problem is that CDG doesn't really have third party / membership lounges in most terminals, and that 2F is also an absolute hell unless you have lounge access. But that would probably just make me not fly AF instead of trying to chase status with them (for now I get it because they're a good airline so I'm happy to book them anyway).

But when we go beyond CDG, AFKL lounge access is not really something that should encourage loyalty, because they don't really have very interesting lounges elsewhere (including at AMS, unless you're into mice). Unless you're travelling from/via CDG, you can probably get the same (or better) lounges with something like DragonPass and you can become a free agent not buying a 75+ euros more expensive ticket just to get that same lounge, which will repay those more expensive fares quickly