[The Squatter of Amon Rûdh]

To clarify what Boromir88 has just said, weregild is Old English, and literally means 'man-payment' or 'man-price'. It is a form of compensation for death or injury, the purpose of which in early Germanic societies was to avert socially destructive feuds by providing a means of satisfying family honour without resorting to physical revenge. The price for a slave's finger was relatively small, that for a nobleman's sword-arm probably more than the average person could earn in a decade; for the lives of a king and his son, payable to their son and brother, it could be expected to be astronomical.

For Tolkien, Isildur's description of the Ring as 'weregild' parallels Gollum's repeated description of it as a 'birthday present'. It is a self-justifying excuse, intended to put his claim to something that he wants beyond debate. Both are reasonable claims, but neither is honest, and this becomes clear when Isildur announces in his own hand that "It is precious to me...": the reader is intended to realise that the same processes are at work in him that can be observed in Gollum, and that Isildur's expressed reasons cannot be trusted.

The point is that whether or not Isildur could realistically use the Ring is irrelevant. He could no more bear to leave it on the battlefield or allow it to be destroyed than Sméagol could bear to let Déagol keep it. He wanted the Ring; whether or not it would be of any use to him did not signify.