There are too many reasons too list.
There are quite a few reasons why we need a monarch, but the main one is that the monarchy gives huge amounts of revenue to our country. The estates owned by the monarchy pay a lot of tax towards Parliament, and help keep important services running. The Queen can also suggest that leaders meet with her and stop their rule. No offense but given current revelations about our leadership I prefer having somebody who can judge our leaders, rather than allowing them the power to stay in office for years after any public support for them has gone. Those are the main reasons why it is good to have a monarchy in this ountry.