No, not at all.
It's just because 1 bit at a time is transferred in pulses of electricity, at least for the first electric wires, not fiber.
It's just because there are 8 wires in an ethernet cord and they form one byte through various combinations.
Well I mean ISPs will tell you your connection is 8 megabits per second, rather than 1 megabyte per second cause in marketing terms, the first one sounds better.