So the MC's an idiot. Is she planning to go live on the street as a toddler? She might be "ignored" by her familly, but she's got a roof, food, clothes, caring maids, access to a library, etc... The fact she's the only one who doesn't understand there must be a hidden reason and, despite hearing her father and grandfather arguing about "going to such length to hide her from the royal family" in front of her, doesn't ponder this new information and proceed with her plan, doesn't reflect favorably on her intelect.
Her "gotcha move" is just cutting her nose to spite her face.
I think I'm most perplexed about how she's chosen to make this grand accusation before all the servants. Then again, I think that the servants are already well aware that she is being ostracized by her family and with the commotion caused by her grandfather, what's a little extra chaos?
Her father's comment about the treatment being better than being used up by the royal family is insufficient. Her grandfather at least did not understand why he made the comment, since his son did not elaborate. (Though apparently the grandfather also did something which he regrets.)
Even if she's being concealed for good reasons, she has not received any love nor education. Before the reincarnation, she was essentially a doll due to the way she was treated.
She won't be living on the streets. Her uncle stated that her grandfather would take her custody and that's when she asked for a favour in order to force their hands; she got the money from her uncle. To put it simply, she didn't want to leave her fate to a discussion between her father and grandfather. She made a financial argument on her worth to justify her price, and then bought herself away with her uncle's money, so that she would be taken in his custody.
But obviously, just putting money in her father's hand isn't enough, because it's not like he accepted the deal and I'd expect some document to be signed if her custody is being brokered.
So yeah, I'm confused. I'm also very curious about the next chapter but I get the feeling that the resolution of this event will not be satisfying because we still won't have an explanation for what's going on. I mean, I expect her father is going to remain silent and accept the event, while the grandfather takes Magnolia away and does not actually discuss the reason for her mistreatment with his son.