Maybe the authorities who frown on it could answer your questions because I can't think of one. Maybe they don't like anything that could lead to negative controversy and want to promote the integrity of the game?

well in play is allowed over the phone although that is an inconvenience. Its just not allowed online and it was probably put in to protect the bookies.

Eventually the govt will realise online in play betting will generate a lot more revenue for them and they will allow it but who knows when that will occur.