As I’ve said I posted to say FWB do turn into more, because people were saying they couldn’t and the man would never care for her - or worse was manipulating and using her.
Firstly, women are well aware that some FWB turn into more, on account of the fact that we have experienced relationship and so have all our friends, who we discuss dating with,
Secondly, people were saying that he sounded like he's potentially using her and manipulating her largely because of the following:
He is quite a bit older than me. I feel like he is enjoying the fact I like him and that he has ‘power’ over me because I go running as soon as he asks to see me.
Power dynamic is extremely unhealthy and not balanced.
I must admit on a few occasions I have tried to slow things down and I’ve even told him I felt I was more interested than he was. He ‘steps his game up’ when I say things like that but a couple days later we are back to square one and he is being the same.
He plays games when he thinks she's backing off.
He said things along the lines of ‘we could be something special’ ‘I like you a lot and I want to see where things go’. I know these are just words and I think all he was trying to do was convince me to meet him. Now we have met it is clear it is purely sexual relationship for him and he isn’t looking for more.
He wasn't honest about his intentions at the start.
OP is absolutely accountable for her part in this in that if she's not getting what she wants out of the relationship then she should walk away rather than holding onto hope if he's been clear he doesn't want more.
But your advice wasn't just that FWB can turn into relationships (which we all know anyway!) it was that women should pretend to be "chill" and not want anything more even if they do want more. That they should be something they're not in order to attract a man... who then would like the false version of them not the real one, rendering it utterly pointless.
FWB can be great if both parties are on the same page, having fun and enjoying it. FWB cannot be great for both parties if one of them is pretending to be ok with the arrangement while actually feeling anxious and having plummeting self esteem while thinking if they keep shagging the bloke long enough and are "chill" enough then eventually he'll want a relationship.