This is either a scam (against park rules) or a waste of money, or both.
There are some things that a "private planner" could do that are useful but nowhere near $250 per hour useful. With access to My Disney Experience, they could help with planning that people don't know how to or don't want to take the time to do themselves, such as:
Making dining reservations and keep checking for availability
Making special event reservations and keep checking for availability
Making
Lightning Lane reservations in advance at WDW and during the day at WDW and DL
Plotting out a suggested order of attractions based on personal preferences and typical wait times (similar to Genie but more personalized)
Simply booking and planning for clients would be overpriced but not a scam. On the other hand, if the company books reservations "on spec" and then sells them to clients, or uses Annual Pass or DVC discounts its employees have, it would be against the rules.
I can see some value in having a guide who recommends where to go next, watches kids while parents ride coasters, picks up food, provides facts about the parks, and so on, but having a private guide in the parks is against the rules:
https://www.washingtonpost.com/travel/2023/12/11/disney-world-third-party-tours-banned/ Any agency offering this is competing with Disney's own service and may be asked to leave at any time.
If the tour company is in any way implying that they can get quicker access to rides beyond what people can get for themselves (especially people staying off-site who can't do early or late hours), they are scamming.
OP, you could pretend to be interested in this service and ask your friend exactly what the company is offering.