In Ireland we have an elected President whose duties are largely ceremonial (laying wreaths, giving speeches, meeting dignitaries incl newly appointed diplomats

In Ireland we have an elected President whose duties are largely ceremonial (laying wreaths, giving speeches, meeting dignitaries incl newly appointed diplomats etc) but include one v important constitutional duty: to sign legislation into law. It has happened that a President refused to sign without first referring controversial legislation to the Supreme Court. In the UK the Crown has nominally comparable authority but is in fact nothing but a glove puppet, or at least that has been the case to date. See e.g., the Queen's acquiescence to the illegal prorogation of parliament. She did was she was told to do in her own name. Her son may not be so accommodating and this may lead to a constitutional crisis. Some check on an overweening executive is always good.