Most kids find round off back tuck easier, but I don’t allow my gymnasts to do round off back tucks, except in exceptional circumstances.
The technique of a round off back handspring, is to go backwards out of the round off. To go into the back tuck you go up.
The Purpose of the back handspring is to build speed and power, for most gymnasts they will be able to generate a lot more power from the BHS, which will make it easier to move that back tuck onto a layout, a twist, a double etc.
If allowed to work round off back tucks, before the BHS is very solid, then the habit will be to go up out of the round off, and not backwards. Then the BHS will end up going too high, killing its power.
The exception is those who won’t be able to generate the usual power from a BHS due to amd issue like lack of flexibility in the shoulders.