There are issues with using puberty blockers in young children who identify as transgender.
For the MTF child, the penis never develops into a usable size needed for penile inversion GCS. Yes, there are other methods of GCS, but they are more complicated and have issues unique to the procedure used.
Allowing normal teenage development does not have this limitation in penis size and the other masculinizing features are not that severe for teenagers. There are many people who have transitioned into extremely attractive, passable women who transitioned in their teens or early twenties with just Estrogens alone. It is the late transitioner who needs hundreds of hours of beard electrolysis, hair transplants for male pattern balding and expensive facial surgeries to even begin to pass reasonably well.
