Well, for one thing, the antenna doesn't have to be quite as large.
And 100 MHz is lower frequency, not low frequency. AM broadcasts between 540 and 1610 kHz in the US and there are long wave broadcasts of 153-279 kHz in Europe, Asia, and Africa.
Higher frequency signals are easier to radiate, require smaller antennas to transmit and receive, and can support higher bandwidths than lower frequency signals.