“she uses people and then discards them faster than old underwear, when their usefulness for her expires.”
Perhaps Harry’s usefulness won’t expire?
The highest Markle will EVER be is a DUCHESS; never a PRINCESS, and NEVER a QUEEN, unless she can figure out how to Harry's father, brother, sister-in-law, and their kiddos killed in one fell swoop.
OTOH...Kate WILL one day be Queen and Markle, should she last that long, which I doubt, will have to curtsy to her.
Markle doesn't approve of guns, dosen't shoot, doesn't hunt, and won't allow Harry to do those things, or even go to those parties.
She doesn't ride, for all I know, and I know a LOT about her, nor does she do any of the usual Royal/aristo/landed gentry passtimes.
So lets say that she picks the "friends" they have, which aren't of the proper sort ( she's already glommed onto "POSH" Beckham ), and tries to tell Kate what she should do & eat and raise the kids ( she loves telling others what to do ! ), which isn't her place, and then the stifling grind of public duty sets in.
Being a ROYAL isn't some stupid Disney movie!
What if she wants to do something she isn't allowed to do...then WHAT?
This is the highest level she'll ever reach there. Will it be enough? I doubt it!