The monarchy own the land, and many of the buildings that are on that land, or on other land, so rental income is collected, alongside many other sources of income generated, and then (unlike a business) that income, is received by the Treasury, and they pay the Monarchy a annual fee. Whilst you don't seem to want to recognise their place as land owners, and income generators, you probable also don't want to recognise their role, as the 'servants' of the 'government of the day', to provide soft diplomacy, where that government see's fit. That includes, but not limited to, visits to meet other world leaders, attending and speaking at conferences, visiting SME's throughout the UK, and many other functions, all in the aid of the UK.
When you are close minded, and ignorant of the facts, in makes one less tolerant of the truth.