I get your point and agree that most places she would consider she could be confident of playing and IMO be a starter very soon. But she would probably be an underdog to unseat Paige or Azzi as a starter next year for example. She might bump Caroline at the 3, but that would still be a pretty high bar, but certainly doable as a freshman, and if she was recruited with Booker she would on paper be substantially ahead of her for projected minutes.Williams is the only HS junior still on the Naismith HS watch list and is being projected as a Maya Moore level talent. Bret McCormick of All Star Girls Report call her the best recruit he has ever seen. Regardless of where she ends ends up it is the other players that will have to worry about playing time not Mikaylah. It is also only a few short months ago that many BYers ( including me) were concerned about adequate minutes and shots for Azzi, Nika, Paige, Saylor, Aubrey & Caroline while still hoping that UCONN would still land Kiki Rice. Booker and Williams also project a MONSTER defenders ,UCONN could use either or both and I hope the UCONN staff is still heavily involved.
Recruiting is a difficult process with many tradeoffs. Make it very clear the top prospect is your number one priority for a position, and your plan B (possibly Booker) might lose interest and move on elsewhere. Show too much interest in the plan B player that might be more probable, and you could lose out on the chance of getting the top dog, although I generally agree the downside in that strategy is less, because as you say the best player, if considered a generational talent like Williams, might not have to worry about playing time.
The difference with us vs. other teams is we will have two projected starters with experience, who were also considered generational talents already penciled in at PG and SG, and a SF we could probably be happy with for the rest of her Uconn career. Williams would still find playing time and would ultimately start, but if she wants to start her whole career, this is one of the few places where that is uncertain.

. We'll see.