Even for the girls that are nakedly (hoho) and exclusively motivated by an envelope of cash, there's still an obvious difference between their interactions with us and a WG's; they can be as discerning as they like in a way that a WG cannot. Obviously the extent to which any given girl makes use of this power is ultimately up to them and will naturally vary a lot. But they can insist on getting to know you at least somewhat, know what you look like, on having a video call, meeting in public etc. So they may not be in love with you, or find your jokes very funny, but there's an element to which they nonetheless chose you.
Or, put another way: would they be shagging you if you weren't paying them? No. Would they shag anyone that would pay them? Also no. This distinction inevitably shifts the whole vibe somewhat, and for a lot - almost all? - the girls on there, this ability to choose is what 'allows' them to do it. WGs, meanwhile, basically have to fuck whatever stumbles through their door (unless, apparently, you're black.)
(Incidentally I absolutely believe there are a ton of girls on there whose hearts aren't shrivelled lumps of clay, for whom the goal may well not remotely be "find love" but who, nonetheless, can find genuine enjoyment in their dealings with guys on Seeking. Ultimately it's a human interaction like any other, and so it's capable of sparking a connection between the right people. Anyone who thinks they can just turn this off is fooling themselves, or possibly they're a former child soldier with severe Asperger's.)