No worries mate.

You have basically answer your question that it really is not needed.

Another aspect to consider is bandwidth and this is one of the reason why it is not being broadcasted to you via digital format.

The bandwidth, @ 60Hz refresh rate, required for the HDTV signals is as follows.

720p, 1280x720 (83 MHz)
1080i 1920x540 (93 MHz) only half of the 1080 horizontal lines are displayed at once.
1080p, 1920x1080 (186.6 MHz)

Note that the difference is double between 1080i and 1080p. This changes the costs significantly.

The formula to calculate bandwidth is

BW = [(TP x Vt) /2] x 3
Where BW = Bandwidth in Megahertz (MHz)
TP = total pixels (horizontal x vertical)
Vt = picture refresh rate in Hertz (Hz)