Graphics card commonly equiped with the Dual-Link DVI-I connector, even though their cards only feature a single port

[xMax]

full quote from Toms hardware guide:

Graphics card manufacturers most commonly equip their products with the Dual-Link DVI-I connector, even though their cards only feature a single port.

what is the point of having dual link DVI-i when the card only has 1 TMDS transmitter and only supports single link DVI-I.