Hilary Cass said in an interview that the cohort of children who could benefit from puberty blockers are the boys who have been socially transitioned very early for whom the prospect of puberty is extremely distressing. She has also said that she wants clinical oversight as early as possible, presumably so as few as possible young boys are socially transitioned and conditioned to fear puberty.
For girls, Cass identified that testosterone will achieve a lot of the desired effects without the need for puberty blockers and if girls don't want periods they can go on the pill.
I think any trial will be very limited in who qualifies. Remember, it has been noted that it is not possible to know who will persist in their transgender identity and who will not but it is known that puberty blockers lead on to other medical steps, hormones and surgery.
Having the puberty blocker ban sends a strong message. Puberty blockers cannot be a first line of treatment. Clinicians will have to justify, why this child? What are the circumstances that make this child exceptional and means they should be exempt from the ban? For parents it's fantastic news if they want to protect their child from the medical route. It makes it so much easier for them to say, no, thank you, to puberty blockers.