True, but the other reason for a "digital" aerial (wideband) is that the digital transmissions are broadcast,on a typical transmitter site, many channels away from the analogue transmissions. For example, my local TV transmitter's analogue transmissions are all in Group C/D high up the band, whereas the digital mux's are spread all over the band, some in Group B which requires a slightly larger aerial (because the frequency is lower, Group A being the largest). To overcome this, wideband (digital)aerials are designed to cover the whole UHF band, although usually with reduced performance.Further, for anyone considering chaning their aerial...
Wait until the changeover, the only reason you might need a new aerial now, is that the transmitted digital signal is low in strenth to prevent interference with the analog (normal) transmission, so you would need a high gain aerial to receive digital.
However when they turn the analogue transmitters off, they will crank up the digital signal strength which will be able to be received by your trusty rusty 20 year old clothes line on top of your house.