If you've not actually experienced them in person, it might help to think of them as small savory (not sweet) cakes, typically served hot. Generally salty and fairly high in fat. They serve much the same role as croissant, but from an area where much of the flour was "pastry" flour which lacks the structure and tensile strength for yeast - raised bread.

An American biscuit is actually a Scottish scone. (Note, not what most people in the US or England know as a scone but a specific item historically made in Scotland that is identical to the US biscuit).

Source: my grandfather made them.

As to gravy: yes. Odd.