That's true, but the term itself is archaic; at the time (early 19th century) the most widespread gaseous fuel was coal gas, also known as "town gas" because we

That's true, but the term itself is archaic; at the time (early 19th century) the most widespread gaseous fuel was coal gas, also known as "town gas" because we piped it to urban homes for lighting. There's not much need for the distinction anymore, plus "methane" aligns with the other trade names for other fossil gases (propane, butane).