What was the point of acquiescing to the GFA?

Ireland, Britain, colonisation, colonization, colonialism, Irish, Free State, Westminster, Leinster House, Stormont, Fine Gael, Fianna Fáil. Workers' Party, Provisional Sinn Féin, Republican Sinn Féin, Irish Republicanism, Irish nationalism, compromise, sell out, decommissioning, surrender, Good Friday Agreement