It wasn’t popular at first as it was quite heavy and easy to lose. But they have survived with a new reverse design most years and have an expected life span of 40 years. The metal in the coin is worth about 4p.
I read some reports that said it was called the Maggie after Margaret Thatcher ie rough round the edges and wanting to be a sovereign.
I have to say I think someone is trying to re-write history as I never heard anyone call it that although I do remember Mrs Thatcher using the royal when announcing; “we are a grandmother” .
FYI The Isle of Man minted a £1 coin some years earlier.